On 22 June 2026, the Indian National Centre for Ocean Information Services (INCOIS), Hyderabad, released its first specialized El Niño bulletin aimed at India's maritime sectors — fisheries, shipping, coastal industry and port operations. The bulletin confirms that the ongoing El Niño event is still developing and is expected to peak in winter (November 2026–January 2027), keeping sea-surface temperatures (SST) in the Indian Ocean above normal until April–May 2027. It warns of thermal stress on the marine ecosystem of the northern Indian Ocean (both the Arabian Sea and the Bay of Bengal), with risks of coral bleaching, marine heatwaves and a fall in fish catch (especially sardine and mackerel). The Bay of Bengal is forecast to stay rough through the monsoon with possible coastal erosion and flooding on the east coast, while the Arabian Sea and west coast are expected to be calmer than usual. The next bulletin is due in the second week of July 2026.
For an NDA aspirant, this single release is a goldmine: it bundles an institution (INCOIS, the Ministry of Earth Sciences), a core physical-geography concept (El Niño / ENSO) and its monsoon link — three of the most heavily tested strands in the GAT General Studies paper. Let us unpack each properly.
What INCOIS is — and where it sits
The Indian National Centre for Ocean Information Services (INCOIS) is an autonomous body established in 1998 and headquartered at Hyderabad (Telangana). It functions under the Ministry of Earth Sciences (MoES) and is a constituent unit of the Earth System Science Organisation (ESSO), the executive arm of the MoES. Internationally, INCOIS is a permanent member of UNESCO's Intergovernmental Oceanographic Commission (IOC) and runs one of the regional tsunami early-warning service providers for the Indian Ocean.
INCOIS exists to turn ocean observations into usable advisories for fishermen, shipping, coastal communities and government agencies. Its flagship services are worth memorising as a set:
- Potential Fishing Zone (PFZ) advisories — using satellite SST and ocean-colour (chlorophyll) data to tell fishermen where shoals are likely, saving fuel and search time.
- Ocean State Forecast (OSF) — daily forecasts of waves, currents, winds and SST for safe sea operations.
- Indian Tsunami Early Warning System (ITEWS) — set up after the 2004 Indian Ocean tsunami, it issues bulletins for the Indian Ocean rim.
- High-wave, swell-surge and storm-surge alerts for the coastline.
The new El Niño bulletin is simply a new product in this stable — the first time INCOIS has issued a dedicated advisory translating a Pacific-basin climate signal into concrete impacts for Indian seas.
The Ministry of Earth Sciences family
NDA loves the "which body does what" question, so fix the MoES institutional map. The Ministry of Earth Sciences oversees the country's atmospheric, ocean, seismology and polar science. Its principal institutions:
- India Meteorological Department (IMD), New Delhi — the national weather and monsoon-forecasting agency (founded 1875).
- Indian Institute of Tropical Meteorology (IITM), Pune — research on monsoon and climate; it develops the Monsoon Mission and climate models.
- National Centre for Medium Range Weather Forecasting (NCMRWF), Noida — medium-range (3–10 day) numerical weather prediction.
- INCOIS, Hyderabad — ocean information and advisory services (today's news-maker).
- National Centre for Polar and Ocean Research (NCPOR), Goa — India's polar (Antarctic/Arctic) and Southern Ocean research; runs stations like Maitri, Bharati (Antarctica) and Himadri (Arctic).
A clean pairing for revision: IMD = weather/monsoon · IITM = monsoon research · NCMRWF = medium-range forecasts · INCOIS = ocean services · NCPOR = polar research. This kind of matching item appears almost every cycle in the daily NDA current affairs GK set.
El Niño and the Southern Oscillation (ENSO) — done properly
The heart of this story is El Niño, the warm phase of a coupled ocean–atmosphere see-saw called the El Niño–Southern Oscillation (ENSO). To understand it, start with normal (neutral) conditions in the tropical Pacific.
Normal conditions. The trade winds blow from east to west (from the Americas towards Indonesia). They drag warm surface water westward, piling it up in the western Pacific (the "warm pool" near Indonesia and Australia), where the sea is warm and rainfall is heavy. Off the South American (Peru) coast in the east, this westward removal of surface water allows cold, nutrient-rich water to well up from below (upwelling) — feeding one of the world's great fisheries. The air rises in the warm west and sinks in the cool east; this great east–west loop of rising and sinking air over the Pacific is the Walker Circulation.
El Niño conditions. Every few years (roughly 2–7 years) the trade winds weaken or reverse. The warm pool sloshes back eastward, so the central and eastern equatorial Pacific warms abnormally — this warming of the central-eastern Pacific is El Niño (Spanish for "the boy child", named by Peruvian fishermen because it often appeared around Christmas). The upwelling off Peru shuts down, fisheries collapse, and the zone of rising air and rainfall shifts east towards the central Pacific — i.e. the Walker Circulation weakens/shifts.
La Niña conditions. The opposite, cool phase: the trade winds strengthen, the central-eastern Pacific becomes colder than normal, the warm pool and rainfall press even harder into the western Pacific, and the Walker Circulation intensifies.
The Southern Oscillation is the atmospheric half of the same coupled system — the see-saw of surface air pressure between the eastern Pacific (Tahiti) and the western Pacific/Indian Ocean (Darwin, Australia). When pressure is high at Tahiti it is low at Darwin, and vice versa. The index that tracks it is the Southern Oscillation Index (SOI): a negative SOI accompanies El Niño, a positive SOI accompanies La Niña. The crucial conceptual point for the exam: El Niño (the ocean warming) and the Southern Oscillation (the pressure see-saw) are two faces of one phenomenon — hence "ENSO".
Why El Niño hurts the Indian monsoon
This is the single most examinable consequence. The Indian summer (southwest) monsoon is driven by a land–sea pressure contrast and by moisture-bearing winds; it is also linked, through the Walker Circulation, to events in the Pacific. During an El Niño:
- The rising-air (rainfall) branch of the Walker loop shifts east to the central Pacific, and a compensating sinking-air branch sets up over the Indian region and the Maritime Continent, which suppresses convection and rainfall over India.
- The cross-equatorial monsoon flow is dampened, weakening moisture transport to the subcontinent.
The net effect: El Niño years tend to bring below-normal monsoon rainfall and, in strong cases, drought. Historically a majority of major Indian droughts (e.g. 1972, 1987, 2002, 2009, 2015) coincided with El Niño. It is not a one-to-one rule — some El Niño years escape with near-normal rains — but the statistical tendency to suppress the monsoon is well established, and that is the answer NDA expects. La Niña, conversely, tends to favour a good or above-normal monsoon. If you are building this foundation, our NDA geography study material sets out the monsoon mechanism and ocean–atmosphere links in full.
The Indian Ocean Dipole — the local modulator
El Niño is a Pacific phenomenon, but the Indian Ocean has its own mode that interacts with it: the Indian Ocean Dipole (IOD), sometimes called the "Indian Niño". The IOD is the difference in SST between the western Indian Ocean (Arabian Sea, near the Horn of Africa) and the eastern Indian Ocean (off Sumatra/Indonesia):
- A positive IOD = warmer west, cooler east. It tends to strengthen the Indian monsoon and can partly offset the drying effect of an El Niño.
- A negative IOD = cooler west, warmer east, which tends to weaken the monsoon and can aggravate an El Niño's impact.
The takeaway: the monsoon in any given year is the net result of the Pacific signal (ENSO) and the Indian-Ocean signal (IOD) acting together. A positive IOD rescuing the monsoon during an El Niño (as happened in some years) is a favourite "explain the exception" point. This ocean-system literacy is exactly what the general knowledge section rewards.
Why the 2026 bulletin reads the way it does
With the science in place, the INCOIS bulletin becomes readable. Because the El Niño is warming the Pacific and, in turn, keeping Indian Ocean SST above normal, the agency forecasts:
- Thermal stress on the northern Indian Ocean ecosystem (Arabian Sea + Bay of Bengal), risking coral bleaching and marine heatwaves — corals expel their symbiotic algae and whiten when water stays too warm.
- A drop in fish catch, especially sardine and mackerel, as stocks migrate to cooler, more suitable habitats and recruitment falls — directly hitting fishermen who rely on INCOIS's PFZ advisories.
- A rough Bay of Bengal through the monsoon with east-coast erosion/flooding, but a calmer Arabian Sea / west coast, widening the safe-operations window there.
This is climate science translated into livelihood and safety advisories — the very purpose of INCOIS, and a textbook example of why India invests in ocean services. Aspirants who want this taught by serving-officer faculty can look at the upcoming Cavalier courses in Delhi.
🎯 Practice MCQs
Q1. INCOIS, which issued the El Niño bulletin, functions under which Union ministry? (a) Ministry of Environment, Forest and Climate Change (b) Ministry of Earth Sciences (c) Ministry of Science and Technology (d) Ministry of Jal Shakti → (b) — INCOIS is an autonomous body under the Ministry of Earth Sciences, and a unit of ESSO.
Q2. INCOIS is headquartered at: (a) Goa (b) Pune (c) Hyderabad (d) Chennai → (c) — INCOIS is based in Hyderabad; NCPOR is at Goa and IITM at Pune.
Q3. El Niño refers to the abnormal: (a) cooling of the central-eastern equatorial Pacific (b) warming of the central-eastern equatorial Pacific (c) warming of the North Atlantic (d) cooling of the Arabian Sea → (b) — El Niño is the warm phase: abnormal warming of the central-eastern equatorial Pacific.
Q4. During a normal (non-El Niño) year, the trade winds over the Pacific blow: (a) west to east (b) east to west (c) north to south (d) they do not blow → (b) — easterly trade winds push warm water westward, allowing cold upwelling off Peru.
Q5. The east–west atmospheric circulation cell over the equatorial Pacific is called the: (a) Hadley cell (b) Ferrel cell (c) Walker Circulation (d) Polar cell → (c) — the Walker Circulation weakens or shifts east during El Niño.
Q6. El Niño generally has which effect on the Indian summer monsoon? (a) strengthens it (b) tends to suppress/weaken rainfall (c) no effect (d) shifts it to winter → (b) — El Niño years statistically tend towards below-normal monsoon rainfall and drought.
Q7. The Southern Oscillation is best described as the see-saw of surface air pressure between: (a) Mumbai and Kolkata (b) Tahiti and Darwin (c) Delhi and Chennai (d) Cape Town and Perth → (b) — the Tahiti–Darwin pressure see-saw; a negative SOI accompanies El Niño.
Q8. A positive Indian Ocean Dipole (IOD) is characterised by: (a) warmer western and cooler eastern Indian Ocean, tending to aid the monsoon (b) cooler western and warmer eastern Indian Ocean (c) uniform warming everywhere (d) cooling of the entire Indian Ocean → (a) — positive IOD (warm west, cool east) tends to strengthen the monsoon and can offset an El Niño.
📋 How this gets asked (PYQ pattern)
ENSO is one of the most reliably repeated NDA/CDS geography themes. Examiners test: the definition of El Niño (warming of the central-eastern equatorial Pacific) versus La Niña (cooling); the direction of the trade winds and upwelling off Peru in normal years; the Walker Circulation by name; the Southern Oscillation / SOI and the Tahiti–Darwin pressure see-saw; and above all the El Niño → weak Indian monsoon link, often as an assertion–reason or "which statements are correct" item. The Indian Ocean Dipole (IOD) is the rising sub-topic, usually paired with ENSO to test whether you know the Indian-Ocean modulator. On the institutional side, expect match-the-body questions across IMD, IITM, NCMRWF, INCOIS and NCPOR and their parent Ministry of Earth Sciences, plus INCOIS services like PFZ advisories, Ocean State Forecast and tsunami warning. The fresh 2026 hook is INCOIS's first specialized El Niño bulletin and its forecast of an El Niño peaking in winter 2026–27 with above-normal Indian Ocean SST, coral bleaching and reduced fish catch — ready-made "which body issued it / what does it warn of" framings.
Studying for NDA or CDS? Ocean–atmosphere systems like ENSO and the monsoon are guaranteed geography marks and a strong SSB lecturette topic — easy once the Walker Circulation, El Niño and IOD click into place. Track our daily NDA current affairs and prepare with serving-officer faculty in the upcoming Cavalier courses in Delhi.
✍️ Written by Col D.N. Sharma — Veteran, Indian Army; SSB & defence-studies faculty at The Cavalier. Reviewed by the Cavalier Faculty Desk. The Cavalier, founded by ex-Army officers, has trained NDA/CDS/SSB aspirants since 2001 (Facebook · YouTube).
Source: PIB release, 23 June 2026 (Release ID 2277120, Ministry of Earth Sciences). Facts cross-verified.