Drought (trigger-1) assessment in Maharashtra at Sub-district Level in the 21st century using multiple SPI and Dry Spell combinations

Drought is one of the most serious natural hazards worldwide, and its impacts have become more severe with climate change. Between 2000 and 2019, drought affected more than 35% of the global population. It has significant socio-economic and environmental consequences, particularly in regions highly dependent on rainfall for agriculture.  As global water demand is expected to rise by over 50% by 2050, understanding and managing drought risk has become more important than ever.

In India, around 70% of crop water requirements rely on monsoon rainfall, making drought a major threat to both food security and rural livelihoods. Maharashtra is among the most drought-prone states in the country. In 2023, nearly two-thirds of the state experienced drought-like conditions. The existing drought declaration process in India follows the Manual for Drought Management (2016) and incorporates parameters such as rainfall, crop conditions, groundwater levels, and reservoir storage. However, the declaration timeline (October 31 for Kharif and March 31 for Rabi), limited real-time monitoring, and data availability challenges hinder timely relief and mitigation efforts. Although dashboards like the India Drought Monitor and Maharashtra Drought Assessment Tool (MahaMADAT) provide district-level insights, there remains a gap in localized drought monitoring and early warning systems.

This study focuses on improving localised drought monitoring by analysing Drought Trigger-1 conditions in Maharashtra at the sub-district level from 2001 to 2023. The analysis uses multiple combinations of the Standardized Precipitation Index (SPI) at 1,3,6,9,12,15,18,21,24 time-scales along with dry spell thresholds of 1 mm and 2.5 mm. By combining multiple SPI time scales with 2 different dry spell thresholds, the study evaluates how often and where Trigger-1 conditions are met across different years and climatic phases.

The results provide a clearer picture of the spatial and temporal patterns of drought in Maharashtra during the 21st century. This work highlights critical hotspots where drought conditions frequently emerge and identifies years with widespread trigger activation. By examining spatial and temporal drought trends, the study provides insights into how current drought assessments can be improved. The findings can support more effective drought early warning by strengthening the understanding of trigger behaviour at a finer scale than currently available in national dashboards.

The finding will also contribute to the development of more effective early warning frameworks, supporting policymakers, researchers, and disaster management authorities in mitigating the impact of drought in Maharashtra and similar regions.