Origin, incidence and impact of droughts over India and remedial measures for their mitigation

Abstract

The paper highlights the factors which tend to reduce the Indian monsoon rainfall substantially. These are: Eurasian snow accumulation during December–March, El Nino with warming phase of the eastern equatorial Pacific [0–10°S, 80°W–180°W], long periods of ‘break’ in the monsoon and poor westward penetration of monsoon low-pressure systems.

Utilising the joint criteria based on specified threshold values of the percentage departure from normal for area-averaged Indian monsoon rainfall and of the percentage Indian area under deficient monsoon rainfall, the years of all-India drought have been identified. Enhancing these criteria suitably, years of severe and phenomenal droughts have also been identified. India experienced 18 droughts during 1871–1990, of which 10 were severe and 5 were phenomenal. While the periods 1901–20 and 1961–80 had the highest frequency of drought, 1921–40 had no drought at all. Most of the severe, and all the phenomenal droughts, occurred in the El-Nino-cumwarming phase which, therefore, needs to be carefully monitored.

The remedial measures which can be actively pursued are effecting improvements in agriculture and in rural economy, according high priority to population control, initiating suitable insurance schemes, generating confidence amongst the affected people and making adequate financial provision to render relief effectively and quickly to drought-hit communities.