Core definition
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO), involving unusually warm conditions in the equatorial Pacific Ocean. ENSO is a coupled ocean–atmosphere phenomenon; La Niña is its cool phase.
Why it matters to India
ENSO can influence Indian summer monsoon rainfall. El Niño conditions are often associated with a greater risk of weaker rainfall, but the relationship is not automatic: Indian monsoon outcomes also depend on other oceanic and atmospheric conditions.
Exam-ready points
- ENSO describes linked changes in the tropical Pacific Ocean and atmosphere.
- El Niño is the warm phase; La Niña is the cool phase.
- The Indian summer monsoon generally occurs from June to September.
- Monsoon effects should be described as a tendency or risk, not a guaranteed outcome.
- Preparedness may involve agriculture, reservoirs, food supplies, power, water and rural livelihoods.
Common mistake
Do not write “El Niño always causes drought in India.” A safer statement is: “El Niño can increase the risk of weaker monsoon rainfall, but the final outcome depends on several interacting conditions.”
Evidence references
- India Meteorological Department: ENSO phases and impacts on Indian summer monsoon rainfall
- Press Information Bureau, 7 July 2026: El Niño, monsoon risk and preparedness context
Quick self-check
- Is El Niño the warm or cool phase of ENSO?
- Why should its effect on the Indian monsoon not be presented as certain?
- Name two sectors that may require preparedness during a weak monsoon.