Tamil Nadu among prominent drought hotspots as southern peninsular India sees strongest drought trend: study
The Ramaiyanpatti reservoir near Dindigul in Tamil Nadu has dried up due to lack of rain. (Photo file) | Photo credit: KARTHIKEYAN G
Tamil Nadu is among India’s most drought-prone areas, as a new 52-year analysis found that southern peninsular India, the region that includes Tamil Nadu, has seen the strongest long-term increase in drought-affected areas among the country’s four broad climate zones.
The study, “Evolution of climate extremes in the Indian subcontinent using the revised CEI,” published in the International Journal of Climatology, analyzed daily precipitation and temperature data from 1971 to 2022 to assess changes in many climate extremes. The researchers developed a revised Indian Climate Extremes Index (IndCEI) that combines seven indicators, including heat, drought, dry season and heavy rainfall.
The study found a strong positive trend in drought-affected areas over southern India, the strongest of the four regions. While less than 10% of the region was affected by drought in the period before the 1990s, more than 40% of the region was affected by drought a few years after 2000. The researchers noted that severe and persistent drought conditions were particularly evident during 2010 and the early 2020s.
The study’s regional classification places Tamil Nadu in southern peninsular India. A media note accompanying the research identifies Tamil Nadu, along with Odisha and Andhra Pradesh, among the eastern coastal states where the drought-affected area increased by 20-30% during 2011-2021 compared to the 1980s.
The researchers used the Standardized Precipitation-Evaporation Index (SPEI) to assess the drought. Unlike an indicator based only on precipitation, the SPEI includes precipitation as well as potential evapotranspiration, thereby capturing the effect of rising temperatures on water availability.
The findings also point to increasing heat stress over southern India. The area of high extremes in maximum temperatures has increased in southern peninsular India, especially since 2010. Scientists said the increase in exposure to heat could be related to declining rainfall, urban heat island effects and the broader effects of climate change.
The temperature index, which combines temperature and humidity to indicate heat stress, also showed a steady increase over southern India. The study attributes the intensification in part to rising minimum temperatures and high humidity associated with the region’s proximity to the Bay of Bengal. Urbanization and higher sea surface temperatures have also been identified as factors that could intensify heat stress.
However, the study found that consecutive dry days do not show a significant long-term increase over southern India. The researchers noted strong interannual variability, including a significant peak in 2002, but the overall trend was nearly flat. They cautioned that using the May–October period for this indicator may have dampened the long-term trend due to the inclusion of pre- and post-monsoon months.
The researchers said the findings underscore the need for region-specific adaptation, particularly drought tolerance in southern India. An accompanying media report calls for a cross-sectoral response involving agriculture, water, health and infrastructure, along with more detailed monitoring to identify localized climate extremes.
The study was conducted by scientists from the National Center for Medium Range Weather Forecasting, India Meteorological Department and Atria University using IMD datasets of 1° × 1° gridded precipitation and temperature covering the period 1971–2022.
Published – 26 Sep 2026 20:32 IST