EL Nino associated with the formation of the South West Monsoon of India is

El Niño is defined as an abnormally warm ocean current that appears periodically along the coast of Peru and Ecuador [1]. Under normal conditions, the cold Peru (Humboldt) current flows along the South American coast, but during El Niño years, this is replaced by a warm surface current [4]. This oceanic warming is the oceanic component of the El Niño-Southern Oscillation (ENSO) [2]. The phenomenon involves a massive pool of warm water shifting from the western Pacific toward the eastern equatorial Pacific [2]. This shift disrupts global atmospheric circulation, including the Indian monsoon system, often leading to weaker monsoon rainfall over India. While it is closely linked to atmospheric pressure changes (Southern Oscillation) and wind patterns, the term 'El Niño' specifically refers to the oceanic warming phase [4].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 29: El Nino, La Nina & El Nino Modoki > El Nino Southern Oscillation (ENSO) > p. 413
2. [4] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > EL-NINO AND THE INDIAN MONSOON > p. 9
3. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > el nino (southern oscillation) and indian Monsoon > p. 54