Asian Journal of Geographical Research

Mapping the Global Research Landscape of Indigenous Knowledge in Disaster Management: A Critical Narrative Review of Research Evolution, Thematic Patterns and Future Directions

K. P. Haneena Sulthana — 2026-09-24

Indigenous knowledge has moved from the margins of disaster scholarship towards formal recognition in disaster risk reduction policy, yet the research field remains conceptually uneven, geographically selective and methodologically dominated by context-specific case studies. This critical narrative review maps the evolution of scholarship on Indigenous, traditional and local knowledge in disaster management; identifies recurrent thematic patterns; evaluates the strengths and limitations of the evidence base; and develops priorities for research and governance. Literature published from 1 January 1995 to 18 July 2026 was considered, with older or adjacent foundational work retained where necessary to interpret conceptual developments. The synthesis indicates a marked transition from early documentation of environmental cues, oral hazard memory and vernacular coping practices towards frameworks for knowledge integration, co-production, pluralism, epistemic justice and Indigenous knowledge sovereignty. Research expanded substantially after the 2004 Indian Ocean tsunami and gained policy legitimacy through the Sendai Framework, but institutional practice has not kept pace with normative recognition. Evidence is particularly strong in demonstrating that place-based observation, oral history, social memory, livelihood practice and culturally grounded communication can improve the local intelligibility of hazard information. Evidence is weaker for causal claims that particular Indigenous-knowledge interventions independently reduce mortality, economic loss or long-term vulnerability, because retrospective case studies, small purposive samples, limited counterfactuals and short follow-up remain common. The literature also reveals persistent tensions around scientific validation, power asymmetries, intergenerational transmission, climate non-stationarity and the extraction of knowledge into external databases. Future progress requires Indigenous-led research governance, longitudinal and comparative designs, multilingual and regionally inclusive evidence mapping, evaluation of policy implementation, and community-controlled digital infrastructures. The field is therefore best understood not as a search for a universal method of “integrating” knowledge, but as an evolving effort to create legitimate, reciprocal and context-sensitive relationships among distinct knowledge systems in disaster risk governance.

Indoor Environmental Quality and Occupant Comfort in Educational Buildings in a Tropical Climate: A Critical Review of the Nigerian Evidence

Alonge Eniola O. — 2026-09-26

Educational buildings in tropical, low-resource settings are routinely occupied under conditions of high ambient heat, humidity, natural ventilation and constrained energy supply, yet the indoor environmental quality (IEQ) delivered by these buildings, and its consequences for occupant comfort, health and learning, remains unevenly documented. This narrative review critically synthesises the empirical literature on thermal, indoor air quality (IAQ), visual and acoustic conditions in Nigerian primary, secondary and tertiary educational buildings, situating this evidence within the broader international literature on IEQ in schools. Sources were identified through structured searching of multidisciplinary and subject-specific databases, institutional repositories and citation tracking, with eligibility restricted to empirical or review studies addressing measured or perceived IEQ parameters in occupied educational settings. The review finds consistent evidence that naturally ventilated Nigerian classrooms operate with neutral and acceptable comfort temperatures several degrees above internationally codified thresholds, reflecting genuine adaptive capacity among occupants, although this evidence remains geographically concentrated, methodologically heterogeneous in exposure duration and thermal indices used, and drawn disproportionately from few climatic zones. Indoor air quality studies reveal a persistent tension between ventilation-adequacy indicators, which frequently appear satisfactory by carbon dioxide criteria, and simultaneously elevated particulate, biological and thermal loads linked to overcrowding, combustion sources and inadequate sanitation infrastructure. Daylighting studies point to widespread underperformance against recommended illuminance thresholds despite abundant equatorial solar resource, a paradox attributable to fenestration design, glare-avoidance behaviour and unreliable electricity supply. Acoustic evidence, though sparse, associates externally generated traffic and generator noise with reported disturbance and adverse health symptoms among students. Across domains, the strength of causal inference linking IEQ to academic performance remains limited by cross-sectional designs, reliance on self-report, small and geographically clustered samples, and an almost complete absence of longitudinal or intervention studies within Nigeria specifically. The review identifies methodological convergence around adaptive thermal comfort theory as a genuine advance, alongside persistent, unresolved gaps in multi-domain IEQ assessment, socioeconomic and gender-differentiated exposure, and the translation of empirical comfort data into enforceable design guidance and building regulation. Priorities for future research include longitudinal and intervention-based designs, standardised multi-parameter monitoring protocols suited to resource-constrained institutions, and closer integration between empirical comfort science and Nigeria’s building regulatory framework. The synthesis offers a defensible evidence base for architects, engineers, educational planners and policymakers seeking to improve learning environments in tropical, energy-constrained contexts, while cautioning against uncritical transfer of temperate-climate comfort standards to Sub-Saharan African educational settings.

Who Can Reach a Service? Zone-Level Measurement of Convenient Access to Public Transport in Bhopal, India

Jainoo Singh Choudhary — 2026-09-09

Aims: This study measures Sustainable Development Goal indicator 11.2.1 for Bhopal Municipal Corporation and its nineteen administrative zones and examines whether a single citywide value obscures spatial differences relevant to service planning.

Study Design: Quantitative spatial analysis using a geographic information system.

Place and Duration of Study: Bhopal Municipal Corporation, Madhya Pradesh, India, August 2026.

Methodology: The analysis used the operator’s register of 396 surveyed bus stops, five railway stations, eight operational metro stations, and the constrained Bondarenko 2020 population surface at approximately 100-metre resolution. Following the custodian definition, Euclidean catchments of 500 m around low-capacity stops and 1 km around high-capacity stations were constructed in UTM Zone 43N. Accessibility was calculated on population and land-area bases for the corporation and each zone.

Results: Convenient access extends to 1,492,687 residents, representing 70.2 per cent of the population, while covering 40.8 per cent of land area. Zone-level population access ranges from 40.2 to 98.9 per cent, and land-area access from 17.2 to 97.9 per cent. Of 632,451 residents beyond the threshold, 36.9 per cent are concentrated in three peripheral zones containing 22.2 per cent of the population. Accessibility is negatively associated with the logarithm of zone area (r = -0.738). Completion of metro Phase 1 raises citywide population access to 75.2 per cent, while the peripheral deficit remains substantially unchanged.

Conclusion: Administrative disaggregation reveals spatial differences concealed by the citywide indicator and provides a more informative basis for identifying where accessibility deficits are concentrated.

Environmental and Socio-Economic Impacts of Shared Mobility Services in the City of Kigali, Rwanda

Marie Ange Musanganya — 2026-09-05

Aims: This study assessed the environmental and socio-economic impacts of shared mobility services in the City of Kigali, Rwanda, with particular emphasis on their contribution to sustainable urban transport, environmental improvement, and livelihood enhancement.

Study Design: A convergent parallel mixed-methods research design was employed.

Place and Duration of Study: The study was conducted in the City of Kigali, Rwanda, among users of various shared mobility services, including bus commuters, motorbike-taxi users, ride-hailing users, and private car owners. Data collection was carried out in 2026.

Methodology: Quantitative data were collected from 400 respondents using structured questionnaires, while qualitative information was obtained through semi-structured interviews with nine key informants representing urban planning institutions, transport regulatory agencies, and mobility service providers. Quantitative data were analysed using descriptive statistics, Pearson correlation, and multiple regression analysis, whereas qualitative data were analysed thematically.

Results: The findings revealed that all shared mobility components examined, namely car and bus sharing, motorbike-taxi sharing, digital mobility platforms, and ride-hailing services, were positively and significantly associated with respondents' perceived socio-economic and environmental outcomes (p < 0.05); because both predictor and outcome measures were self-reported, these results reflect perceived rather than independently verified impacts. Car and bus sharing exhibited the strongest association (r = 0.832, p < 0.05). Multiple regression analysis indicated that the four predictors jointly explained 75.6% of the variation in socio-economic and environmental impacts (Adjusted R² = 0.709; R = 0.862; p < 0.05). Respondents reported that shared mobility services contribute to reduced traffic congestion, lower urban emissions, improved accessibility, and the creation of employment opportunities. However, disparities in access were observed among low-income populations and residents of peripheral areas.

Conclusion: Shared mobility services constitute an important pathway towards sustainable urban development in Kigali by generating environmental and socio-economic benefits. The study recommends the development of integrated digital mobility systems, accelerated electrification of shared transport modes, and targeted infrastructure investments to improve accessibility and inclusiveness across all communities.

Robust Inference and Management Prioritisation of Sub-Basin Water-Quality Heterogeneity in the Pra River Basin, Ghana

Frank B. K. Twenefour — 2026-09-07

Aims: River-basin averages may conceal management-relevant differences among tributary systems. This study quantified the magnitude, precision, and management relevance of differences in Water Quality Index (WQI) among the Birim, Offin, and Pra sub-basins of the Pra River Basin, Ghana.

Study Design: Secondary quantitative analysis of an existing cross-sectional, station-level WQI dataset.

Place and Duration of Study: The study covered 150 georeferenced monitoring stations distributed across the Birim, Offin, and Pra sub-basins of the Pra River Basin, Ghana. The secondary statistical analysis was conducted in 2026 using previously developed station-level WQI data.

Methodology: The study did not re-derive the WQI or repeat spatial interpolation. Descriptive statistics and 95% confidence intervals were used to summarise sub-basin WQI patterns. Distributional characteristics were assessed using the Shapiro-Wilk test. Overall differences among sub-basins were evaluated using Welch's one-way analysis of variance, followed by Games-Howell post hoc pairwise comparisons. Effect-size measures were estimated to assess the practical magnitude of observed differences.

Results: Mean WQI was highest in Offin \((120.57 \pm 15.67)\), followed by Birim \((93.33 \pm 10.82)\) and Pra \((74.17 \pm 7.22)\). Welch's test showed significant differences among the sub-basins, \(F(2,89.96)=198.36, p<0.001\). Variance-partition effect sizes were very large \(\left(\eta^2=0.728 ; \omega^2=0.723\right)\), while Games-Howell comparisons showed very large to extremely large standardised differences across all pairwise contrasts.

Conclusion: WQI differed substantially among the three sub-basins, indicating that basin-wide averages may obscure spatial differences relevant to water-quality management. Offin emerged as the highest priority for surveillance and source investigation, Birim as a corrective-monitoring priority, and Pra as a preventive-protection priority. The study provides decision-oriented evidence by quantifying uncertainty and practical effect magnitude while avoiding unsupported attribution of pollution to specific sources.

Impact of Rainfall Variability on LULC and NDVI in Polavaram District, Andhra Pradesh: Using Geoinformatics

M. Karunakara Rao — 2026-09-07

Rainfall patterns significantly influence land use, land cover and vegetation health, which is commonly assessed using the Normalized Difference Vegetation Index (NDVI). This study examines the influence of rainfall patterns on land use, land cover and vegetation health in Polavaram district, utilising data from 2017 and projections for 2025. Variations in rainfall, ranging from low to very high, significantly affect agricultural practices and ecological stability. In 2017, tree cover accounted for 70.97% of the area, while agricultural land comprised 11.8%. By 2025, tree cover is projected to decrease to 67.83%, and agricultural land to 11.36%, indicating shifts in land utilisation. The Normalized Difference Vegetation Index revealed spatial differences in vegetation health, with higher values corresponding to robust ecosystems. NDVI analyses for 2017 and 2025 further demonstrated changes in land cover, with water bodies and built-up areas exhibiting minimal vegetation. These results underscore the need to understand the impacts of rainfall variability on land management, agriculture and biodiversity. The study provides valuable insights for stakeholders to address climate change, enhance agricultural resilience and manage extreme weather events, thereby supporting sustainable development in the region. The research provides valuable insights into how changing precipitation patterns affect land use and vegetation health, which are essential for effective resource management and planning.

Integrated Sedimentological Characteristics and Hydrocarbon Prospectivity of the Ogwashi–Asaba Formation, Southeastern Nigeria

Oludewa Joseph Mode — 2026-09-08

The Ogwashi–Asaba Formation in southeastern Nigeria comprises interbedded sandstone, shale, and lignite units that record variations in depositional processes and provide a basis for preliminary assessment of hydrocarbon prospectivity within the Anambra Basin. This study evaluated the sedimentological characteristics, petrographic features, organic matter content, and depositional significance of selected outcrop successions. Field observations were integrated with grain-size analysis, petrographic examination, and total organic carbon determination using the Walkley–Black wet oxidation method. The sandstone units are predominantly fine- to medium-grained and variably sorted, indicating fluctuations in depositional energy. Petrographic examination shows quartz-rich sandstones with minor feldspar, rock fragments, and accessory minerals, consistent with compositional maturity, sediment recycling, and prolonged transport prior to deposition. Shale and lignite intervals contain appreciable organic matter and represent comparatively low-energy depositional conditions favourable for organic matter preservation. Integrated sedimentological and geochemical evidence supports deposition within a dynamic transitional system influenced by fluvial, deltaic, swamp, lagoonal, and shallow marine processes. Organic-rich shale and lignite intervals indicate preliminary source-rock potential, whereas compositionally mature sandstone units may have reservoir relevance. However, the available evidence is insufficient for definitive petroleum-system evaluation, and further analyses, including kerogen typing, Rock-Eval pyrolysis, vitrinite reflectance, and biomarker studies, are required to constrain hydrocarbon generation potential, thermal maturity, and petroleum-system significance.

Terrain-based Stone Quarrying and Its Socio-economic Impacts in Churachandpur District, Manipur, India

Letminthang Baite — 2026-09-17

Stone quarrying in hilly environments is influenced by terrain, geological conditions and accessibility, while also providing employment to community’s dependent on extractive activities. This study examines the spatial characteristics of stone quarrying and the socio-economic conditions of quarry workers at seven selected sites in Churachandpur District, Manipur, India. Primary information was collected from 100 quarry workers through structured questionnaires, personal interviews and field observations. Geographic information system and remote-sensing techniques were used to analyse quarry locations, elevation, slope and accessibility. The selected quarry sites occur in rugged terrain associated with the Churachandpur-Mao Fault zone. Mean elevations of the sites range from 1,001 to 1,169 m, while mean slopes range from 14° to 17° and maximum slopes exceed 40° at all sites. Labourers constitute 37% of respondents and stone-crusher workers 34%, indicating substantial dependence on manual quarry-related employment. Income varies among occupational groups, with contractors reporting higher daily earnings than labourers, loaders and stone-crusher workers. Positive correlations were observed between age and work duration (r = 0.58) and between work duration and income (r = 0.47). Field observations and reported injuries indicate exposure to hazards associated with steep terrain, loose rocks, machinery, blasting and inadequate protective measures. The findings highlight the interrelationship between terrain characteristics, quarry-based livelihoods and occupational vulnerability and indicate the importance of improved safety practices and terrain-sensitive quarry management.

Institutional Framework and Governance Arrangements for Watershed Management in Makueni County, Kenya

Raphael Kieti — 2026-09-19

Background: Watershed degradation in semi-arid regions of Kenya has emerged as a critical environmental and socio-economic challenge, threatening ecosystem sustainability and rural livelihoods. In Makueni County, increasing pressure from population growth, unsustainable land-use practices, climate variability, and poverty has accelerated soil erosion, deforestation, sedimentation, and declining agricultural productivity, thereby undermining food security and environmental integrity.

Aim: The present study aimed to determine how institutional conditions influenced watershed management in Makueni County, Kenya. The specific objectives were to determine how land-use methods influenced the socio-economic and biophysical conditions of watershed resources in Makueni County and their effects on livelihoods, and how the institutional framework contributed to watershed management in the study area.

Study Design: The study used a descriptive survey research approach to obtain data on the socio-economic characteristics of the study area and historical trends in land use.

Place and Duration of Study: Makueni County, Kenya; September 2024 to April 2025.

Methodology: Structured and semi-structured questionnaires were used to collect data from the community and key informants. The data collected were analysed using the Statistical Package for the Social Sciences (SPSS) and Microsoft Excel 2010. Data from household and key-informant questionnaires and focus group discussion (FGD) notes were processed using thematic analysis to establish leading themes, trends/patterns, relationships, or correlations.

Results: The study established that livelihood strategies and the current natural resources management framework had a negative impact on watershed management, with 92% of respondents reporting that unsustainable utilisation methods led to watershed degradation. The most conspicuous effects of watershed degradation were reduction in vegetation cover, increased soil erosion (82%), diminishing farm sizes (75%), water scarcity (63%), and diminishing grazing land (37%). Several government and non-governmental organisations are actively involved in watershed management in different capacities. However, local community participation in watershed restoration activities and involvement in institutional decision-making remain largely unaddressed, thus compromising the sustainable and holistic integrity of watershed resources.

Conclusion: We conclude that, although some institutional efforts are in place to maintain watersheds in the study area, the approach is uncoordinated and the local community is largely isolated. Despite multiple actors, weak coordination, sectoral approaches, and limited community participation undermine sustainable watershed management. We therefore recommend an integrated and holistic strategy for sustainable watershed management in which the community becomes a central part of policy formulation and decision-making.

Tourist Satisfaction and Homestay Preferences in Leh District, Ladakh: A Cross-Sectional Mixed-Methods Study

Jigmat Norboo — 2026-09-19

Aims: To evaluate tourist satisfaction and accommodation preferences associated with homestay tourism in Leh District, Ladakh, and to examine differences between domestic and foreign visitors while contextualising the findings within contemporary homestay policy.

Study Design: Cross-sectional mixed-methods survey using structured closed-ended items and limited open-ended questions.

Place and Duration of Study: Leh District, Union Territory of Ladakh, India, during May to September 2025.

Methodology: A total of 253 tourists who had stayed in a registered or recognised homestay for at least two nights were included (176 domestic and 77 foreign visitors). Descriptive statistics, Pearson chi-square tests, Welch's independent-samples t-tests, standardised effect sizes, exploratory multiple regression coefficients, and thematic analysis of open-ended responses were used. Because recruitment was purposive and convenience-based, inferential results are interpreted as sample-based associations rather than design-based population estimates.

Results: Homestays were the preferred accommodation type for 64.2% of domestic and 80.5% of foreign respondents; tourist origin was weakly associated with accommodation preference (X²(2)=6.69, p=.035, Cramér's V=.16) and rural-versus-urban preference (X²(1)=5.48, p=.019, Cramér's V=.15). Mean overall satisfaction was 4.1/5 among domestic tourists and 4.5/5 among foreign tourists (Welch t=-5.60, df=181.9, p<.001, d=.70). The largest between-group difference concerned cultural authenticity (3.9 vs. 4.8; d=1.38). Digital accessibility was the lowest-rated dimension in both groups (3.2 and 3.5). Open-ended responses most frequently identified transportation and connectivity constraints, while recommendation and revisit intentions remained high. In the exploratory regression, cultural authenticity (\(\beta\)=.38) and hospitality (\(\beta\)=.29) had the largest standardised coefficients.

Conclusion: Homestay experiences in the surveyed Leh sample were generally rated positively, particularly for hospitality and cultural experience, but digital connectivity, transport access, hygiene, basic amenities, and communication barriers remain important service constraints. The results support differentiated service and marketing strategies for domestic and foreign visitor segments and are broadly consistent with the quality, capacity-building, cultural, and rural-development priorities of the Ladakh Homestay Policy 2023. The cross-sectional non-probability design does not establish causal effects or population prevalence.

Hydrogeochemical Characterisation and Assessment of Mineral–water Interaction in Aquifer Systems of the Niger Delta, Nigeria

Etukudo Nsikan J. — 2026-09-28

Groundwater is an important source of water supply in the Niger Delta, and its chemistry reflects interactions between recharge water and aquifer materials. This study characterised the hydrogeochemistry of selected Niger Delta aquifer systems and assessed mineral–water interaction processes using physicochemical parameters, major dissolved ions and diagnostic ionic relationships. Groundwater was sampled from ten boreholes representing different hydrogeological settings. The samples were analysed for pH, electrical conductivity, total dissolved solids, hardness, . Groundwater pH ranged from 5.82 to 7.21, indicating slightly acidic to neutral conditions, while electrical conductivity ranged from 186 to 842 µS/cm and total dissolved solids from 121 to 548 mg/L. Sodium and calcium were the principal cations, whereas bicarbonate and chloride were the dominant anions. Higher dissolved-ion concentrations and hardness at selected locations indicated greater mineralisation, whereas lower values at other locations suggested comparatively dilute groundwater. The combined hydrochemical evidence indicates that mineral dissolution, silicate weathering and cation exchange contribute to groundwater evolution, with localised chloride enrichment at some sampling locations. Overall, the groundwater chemistry reflects spatially variable interaction between recharge water, aquifer materials and groundwater flow. These findings provide a hydrogeochemical basis for interpreting groundwater quality and supporting groundwater-resource assessment in the Niger Delta.

Geographical Distribution and Potential of Solar Energy Resources in the Dungarpur and Banswara Districts of Southern Rajasthan, India: A GIS-Based Multi-Criteria Assessment

Mahaveer Prajapat — 2026-09-28

Solar energy development in India has been geographically uneven, and the reasons for that unevenness remain poorly understood at the sub-district scale. This study therefore analyses the geographical distribution, technical potential and socio-economic implications of solar energy development in the Dungarpur and Banswara districts of southern Rajasthan, and derives region-specific policy recommendations. The study area covers 8,807 km² and comprises sixteen tehsil units. Two complementary data streams were combined. On the resource side, long-term satellite-derived global horizontal irradiance (GHI) was interpolated to map the solar resource; a composite Solar Potential Index (SPI) was then constructed for each tehsil unit from six indicators weighted by the Analytic Hierarchy Process (consistency ratio 0.06); land suitability for utility-scale photovoltaics was mapped by weighted-overlay multi-criteria decision analysis using irradiance (0.35), grid proximity (0.30), terrain (0.25) and exclusion layers (0.10); and technical potential was estimated separately for five deployment modes, supported by a monthly simulation of a 1 MW fixed-tilt plant. On the demand side, primary data were obtained from 400 respondents in twenty villages by multi-stage stratified random sampling and analysed using percentages, Pearson's correlation, chi-square and t-tests. The results show that annual mean GHI is 5.32 kWh/m²/day in Dungarpur and 5.18 kWh/m²/day in Banswara, declining from north-west to south-east, with a monsoon reduction of 38–40%; the optimum fixed tilt is approximately 20° facing south and a 1 MW plant would generate about 1,614 MWh annually, corresponding to a capacity utilisation factor of 18.4%. Across the sixteen units the SPI correlates most strongly with grid proximity (r = 0.90), road connectivity (r = 0.73) and level land (r = 0.70), but only moderately with irradiance (r = 0.49). Highly suitable land accounts for 10.9% of Dungarpur but only 1.2% of Banswara, and total technical potential is 8,340 MW against an installed capacity of about 135 MW, representing a utilisation rate of 1.6%. Among surveyed solar pump users, irrigated area rose 46%, cropping intensity 25% and net farm income 47%, while irrigation expenditure fell 86%. Taken together, these findings indicate that solar development in this hilly, densely populated tribal region is constrained primarily by terrain, land competition and grid infrastructure rather than by the availability of solar radiation. It follows that policy should move beyond the large solar-park model of western Rajasthan towards decentralised, water-linked and community-owned deployment.

Beyond Parallel Trends: A Confounder-Adjusted, Spatially Explicit Test of Climate–Land-Use Associations in a Western Ghats-Adjacent Semi-Arid District, South India

M. Vasanthakumar — 2026-09-28

Land-use/land-cover (LULC) change and climate variability are often reported together in district-level studies, yet their statistical association is rarely tested after accounting for topographic and anthropogenic influences. This study examines Erode District, Tamil Nadu, a semi-arid district adjacent to the Western Ghats, using a confounder-adjusted and spatially explicit framework. Sentinel-2 imagery was classified for 2016 and 2024 using a Random Forest model, achieving test-set overall accuracies of 75.7% and 74.8% and Kappa values of 0.68 and 0.66, respectively. Agricultural land declined by 8.0%, built-up area increased by 3.2%, and forest and tree cover increased by 14.3%. Climate trends were evaluated across 156 gridded nodes for 1990–2025 using autocorrelation-aware Mann-Kendall testing and Sen's slope estimation. Minimum temperature increased significantly at all nodes (+0.0237 °C/year, p=0.002), while wind speed declined significantly (-0.0059 m/s/year, p<0.001). Logistic regression on a 1 km grid showed that the agriculture-to-built-up transition remained significantly associated with the local minimum-temperature trend after adjustment for elevation, slope, distance to road, and population. Confounder-adjusted models consistently improved model fit, with AIC reductions ranging from 7.9 to 108.3 points. Residual spatial autocorrelation remained significant, indicating unresolved spatial structure. The findings support a replicable framework for testing climate–land-use associations while avoiding causal interpretation.

Dynamics of Urban Land Use and Land Cover Change and its Implications for Ecosystem Services: A Study of Ranchi City, India

Vaishnavi Swami — 2026-09-28

The continuously changing urban landscape due to rapid and haphazard urban growth and industrialisation has posed a serious threat to the urban ecosystem and its sustainability. The study is an attempt to analyse the impact of land use and land cover (LULC) changes on ecosystem service value (ESV). Ranchi, a medium-sized, rapidly growing capital city of Jharkhand state in eastern India, was selected as the study area. The Landsat data for the years 1993, 2008, 2023 and 2026 and the published global value coefficients (VCs) for different ecosystems were used for the analysis. To check the reliability of the estimated ESVs, a sensitivity analysis was carried out using the coefficient of sensitivity (CS). The total estimated ESV of Ranchi city was approximately 14.89 million USD in 1993, 13.51 million USD in 2008, 9.54 million USD in 2023 and 9.13 million USD in 2026. The estimated ESV declined by 35.97% over the 30-year period between 1993 and 2023, followed by a further decline of more than 4% in just three years (2023–2026). The decline aligns closely with rapid built-up area expansion and the corresponding reduction in vegetation and water bodies. The findings of the study call for an effective land-use management policy and its proper implementation to ensure ecological conservation alongside sustainable urban growth of the city.

Spatiotemporal Dynamics of Surface Urban Heat Islands Across Divergent Planning Paradigms: A 25-Year Multi-Temporal Assessment of the Chandigarh Tricity Agglomeration Region (2000–2024)

Manisha Hooda — 2026-09-29

Aims: To examine the spatiotemporal dynamics of Land Surface Temperature (LST), biophysical metrics (NDVI, NDBI), and urban heat stress (UTFVI) over multi-decadal timescales across contiguous regions governed by differing urban planning systems.

Study Design: A multi-temporal geospatial study employing remote sensing technology.

Place and Duration of Study: Chandigarh Tricity Agglomeration Region (Chandigarh Union Territory, SAS Nagar [Mohali] district, and Panchkula district), north-western India; pre-monsoon summer periods (1 March to 31 May) were examined over the 25-year period from 2000 to 2024.

Methodology: Surface reflectance and surface temperature datasets from the USGS Harmonized Landsat Collection 2 Level-2 products for Landsat 5 TM, 7 ETM+, 8 OLI/TIRS, and 9 OLI-2/TIRS-2 were obtained and processed using Google Earth Engine. After applying the CFMask method for cloud filtering, pre-monsoon median composite images were produced to estimate LST, NDVI, NDBI, and UTFVI. Twenty-five-year trend lines, stratified random pixel sampling (n=10,000), and bivariate linear regressions (LST~NDVI and LST~NDBI) were conducted using Google Colab (Python).

Results: Thermal characteristics diverged markedly over the 25-year study period within the agglomeration. Mohali recorded the largest surface-temperature increase, rising by \(5.46^{\circ} \mathrm{C}\) (32.91 °C to \(38.37^{\circ} \mathrm{C}\) ) at a rate of \(1.63^{\circ} \mathrm{C} \cdot\) decade \(^{-1}\), alongside rapid horizontal growth. Chandigarh warmed by \(4.10^{\circ} \mathrm{C}\left(33.16^{\circ} \mathrm{C}\right.\) to \(\left.37.26^{\circ} \mathrm{C}\right)\), while topographically diverse Panchkula warmed by 3.15 °C (33.33 °C to 36.48 °C). Bivariate regression results showed that the thermal forcing associated with built-up land steepened from \(+13.69^{\circ} \mathrm{C} / \mathrm{NDBI}\left(R^2=0.373, p<0.001\right)\) in 2000 to \(+17.43^{\circ} \mathrm{C} / \mathrm{NDBI}\left(R^2=0.264, p<0.001\right)\) in 2024 based on stratified random sampling ( \(n=10,000\) ). In 2024, UTFVI zoning revealed pronounced microclimatic polarisation across the \(1,723 \mathrm{~km}^2\) region: \(43.08 \%\left(742.27 \mathrm{~km}^2\right)\) exhibited excellent thermal comfort, whereas \(43.06 \%\) ( \(741.92 \mathrm{~km}^2\) ) experienced extreme heat stress.

Conclusion: The master-planned green corridors and preserved canopy buffers reduce surface heat build-up relative to unregulated suburban growth on the periphery. Harmonised planning across administrative boundaries, mandatory canopy-cover requirements, and reflective surfaces are important measures for controlling increasing heat stress in the region.