Droughts

1. Meaning, types and diagnostic indicators

Drought is a slow-onset hazard arising when precipitation and available water remain insufficient for a region’s usual environmental and human requirements. Unlike a flood, it rarely has an obvious beginning or boundary. Its severity depends on the size, duration and timing of the water deficit, as well as exposure and vulnerability. A short dry spell can severely damage rainfed crops even when drinking-water reservoirs remain adequate.

Meteorological drought refers to an abnormal precipitation deficit over a specified period and area. Agricultural drought occurs when root-zone soil moisture cannot meet crop requirements at a particular growth stage. Hydrological drought involves sustained deficits in streamflow, reservoir storage or groundwater. Socio-economic drought emerges when reduced water availability disrupts the supply of goods and services, including food, electricity and drinking water.

The Standardized Precipitation Index, or SPI, expresses rainfall anomalies over different timescales; negative values indicate drier-than-normal conditions. The Standardized Precipitation Evapotranspiration Index, or SPEI, also considers atmospheric evaporative demand. These indices complement, rather than replace, observations of soil moisture, vegetation condition, river discharge and groundwater. Distinguish drought from desertification, which is land degradation in arid, semi-arid and dry sub-humid areas resulting from climatic variations and human activities.

• Flash drought develops unusually rapidly when rainfall shortage combines with high temperatures and strong evaporative demand.
• Agricultural drought can precede hydrological drought; groundwater and reservoir deficits may persist after rainfall recovers.

2. Causes and geographical distribution in India

India’s drought risk is closely linked to the southwest monsoon. Delayed onset, prolonged breaks, early withdrawal and uneven rainfall distribution can interrupt soil-moisture replenishment. The all-India seasonal average can therefore obscure severe district-level stress. Intense rainfall concentrated into a few events may generate substantial runoff without maintaining crop-available moisture through the season.

El Niño, the warming of the central and eastern equatorial Pacific, often increases the probability of a weak Indian summer monsoon. However, the relationship is not deterministic: not every El Niño produces drought, and drought can occur without El Niño. The Indian Ocean Dipole, intraseasonal oscillations and regional circulation also influence rainfall. Rising temperatures can intensify drought impacts by increasing evaporation and plant water demand.

Persistent vulnerability is found in western Rajasthan, Kachchh and other parts of Gujarat, and the rain-shadow interiors of Maharashtra, Karnataka, Telangana, Andhra Pradesh and Tamil Nadu. Marathwada, Rayalaseema and Bundelkhand frequently face combinations of erratic rainfall, limited soil-water storage and livelihood dependence on farming. Tamil Nadu’s substantial dependence on the October–December northeast monsoon makes its drought calendar different from that of much of India.

Physical conditions alone do not determine losses. Shallow soils, degraded catchments and limited groundwater storage increase sensitivity to dry spells. In hard-rock peninsular regions, groundwater occurs mainly in weathered and fractured zones with uneven yields. Excessive pumping, water-intensive crops, loss of tanks and poorly managed urban expansion can turn a rainfall shortfall into a major water crisis.

3. Impacts on agriculture, society and ecosystems

Agricultural impacts include delayed sowing, reduced cropped area, poor germination, crop failure and declining yields. Stress during flowering and grain filling is especially damaging. Rainfed farmers are directly exposed, but irrigated agriculture also suffers when reservoirs fail to fill or wells decline. Fodder shortages and reduced drinking water weaken livestock health, affecting pastoralists and mixed crop–livestock households.

Drought reduces farm employment and rural purchasing power, potentially increasing indebtedness and distress migration. Women and children may spend more time collecting water, with consequences for health and education. Poorer households face greater risks because they possess fewer assets, weaker access to irrigation and limited financial buffers. Drinking-water quality can also deteriorate as communities rely on unsafe or concentrated residual sources.

Environmental consequences include declining wetland extent, reduced river baseflow, vegetation stress, habitat degradation and greater wildfire risk where dry fuel is available. Low streamflow weakens the dilution of pollutants. Hydropower generation and water-dependent industries may be disrupted, while thermal power plants can face cooling-water constraints. These effects illustrate why drought management requires coordination beyond the agriculture department.

• A compound drought–heatwave event can simultaneously intensify crop stress, electricity demand and health risks.
• Repeated drought can contribute to land degradation, but drought and desertification are not interchangeable.

4. Monitoring, declaration and institutional response

India’s drought assessment uses multiple indicators because rainfall alone cannot capture agricultural or hydrological stress. The India Meteorological Department monitors rainfall departures, dry spells and drought indices. Satellite-based assessments by institutions including the National Remote Sensing Centre help identify vegetation and surface-moisture anomalies. The Central Water Commission tracks major reservoir storage, while the Central Ground Water Board assesses groundwater conditions.

The Manual for Drought Management, 2016, and subsequent official amendments provide the central framework for assessment. It combines rainfall-related indicators with evidence such as crop sowing, vegetation condition, soil moisture and hydrological conditions, followed by field verification where required. The operational sequence involves identifying a trigger, evaluating impact indicators and checking actual damage. State governments make drought declarations under the applicable procedures.

Disaster governance operates within the Disaster Management Act, 2005, and related national and state arrangements. Relief assistance is available under applicable State Disaster Response Fund and National Disaster Response Fund norms, subject to eligibility and assessment. Such assistance is intended for specified relief needs, not full compensation for every loss. Accurate local data and timely declarations are essential for effective intervention.

• Do not confuse an IMD rainfall-deficiency category with a legal or administrative drought declaration.
• Use district or sub-district evidence: national rainfall averages cannot establish local drought severity.

5. Mitigation and drought-resilient development

Effective management shifts from emergency relief to preparedness. Watershed treatment, contour bunding, vegetative barriers, tank restoration and protection of recharge zones improve infiltration and reduce erosion. Recharge structures must suit local geology and should not intercept essential downstream flows. Groundwater budgets must account for extraction as well as recharge; merely constructing more storage does not ensure water security.

Agricultural adaptation includes locally appropriate short-duration varieties, diversified farming, millets and pulses where suitable, mulching and contingency crop plans. Micro-irrigation can improve application efficiency, but basin-wide savings are not automatic if farmers expand irrigated area or switch to thirstier crops. Atal Bhujal Yojana promotes community participation in groundwater management in selected water-stressed areas, while MGNREGA can support eligible water-conservation and drought-proofing works.

Preparedness also requires protected drinking-water sources, fodder reserves, reliable advisories and social protection. Crop insurance under Pradhan Mantri Fasal Bima Yojana can reduce eligible financial losses but cannot replace ecological adaptation. Long-term resilience depends on aligning cropping patterns and urban demand with dependable water availability, monitoring withdrawals and ensuring equitable access during shortages.

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