In the last week of November, when most of India has long since put its umbrellas away and started planning for winter, the rain arrives in Chennai. It falls on the Marina in grey, unhurried sheets, fills the temple tanks of Kanchipuram to their brims, swells the paddy nurseries of the Cauvery delta — and barely makes the national news, because by late November the country has already mentally filed the monsoon away as a story that finished in September. Tamil Nadu knows better than to file it away so early. It is waiting for India’s other monsoon, the one that blows in the opposite direction from the one everybody remembers.
Ask most Indians to name the monsoon and they will name only one: the great southwest deluge of June to September, the one that fills every schoolbook illustration and every weather bulletin from April onward. The meteorological truth, largely absent from that popular picture, is that the subcontinent actually lives under two distinct wind regimes each year, twins working opposite shifts on the same climate system. The summer twin is the Nairuti — the southwest monsoon, sweeping in from both the Arabian Sea and the Bay of Bengal to deliver roughly three-quarters of India’s entire annual rainfall inside a single four-month window. The winter twin is the Ishanya — the northeast, or retreating, monsoon of October to December, which doubles back over a Bay of Bengal still warm from summer, drinks in fresh moisture from it, and waters the southeastern seaboard precisely as the rest of the country is drying out for the year.
The names for these two systems are considerably older than the science that now explains them. In Telugu, as in Sanskrit before it, the eight cardinal and intercardinal directions each have a guardian deity — the dikpalas, lords of the quarters, a cosmology mapped directly onto the compass. Nairuti, is the southwest, the domain of the deity Niruti, Ishanya, is the northeast, the quarter belonging to Ishaan. Indian tradition, in other words, named its winds for the direction their house lies in, long before anyone possessed an isobar or a satellite image to confirm the geography. It is a naming convention built on pure directional logic, and it has outlived every scientific revision of the underlying physics.
The India Meteorological Department’s own operational classification divides the Indian year into four official seasons: winter, from December through February; summer, or the pre-monsoon season, March through May; the southwest monsoon itself, June through September; and the post-monsoon, or retreating-monsoon, season, October through December. This is the framework against which every forecast, every revision, and every district-level rainfall figure cited anywhere in this cover package has actually been measured, and it is the framework this package uses throughout.
The third of these four official seasons is the one that decides the fate of over a billion people every single year. Between the first of June and the last of September, the Nairuti delivers, on average, 87 centimetres of rain to the country as a whole — the exact benchmark figure against which this year’s shortfall has been measured throughout this cover package, from the opening forecast revision to the reservoir tables in Article 8. Every kharif crop sown across the country, every reservoir management plan drawn up by every state water authority, and a meaningful share of the national government’s own budgetary assumptions about agricultural growth are all staked, each year, on those same four months performing roughly as expected.
The fourth season, arriving six months later, is smaller in total volume but is nowhere near as marginal to the people who actually depend on it as its modest national share might suggest. Tamil Nadu draws close to half of its entire annual rainfall from the returning Ishanya wind alone; coastal Andhra Pradesh takes a substantial share as well, enough to matter directly to the delta agriculture this cover story has followed all issue. The Ishanya is the reason Tamil Nadu’s paddy farmers can plant and harvest a second crop in a single agricultural year where farmers further north cannot; it is why a “failed monsoon,” spoken of casually as a single national event, actually means something structurally different in Thanjavur than it does in Delhi or in Nagpur.
This year’s story, and the story this entire cover package has told from its opening page, belongs overwhelmingly to the Nairuti — the summer monsoon arriving at roughly nine-tenths of itself, its onset delayed, its opening weeks the weakest since 2009, its recovery through July only partial. But it is worth holding the Ishanya in mind precisely because the summer season’s story is not, in the strictest sense, finished until the winter one has also had its say. When October arrives and the wind across the subcontinent finally reverses direction, a parched peninsula — the same peninsula whose reservoirs this package has tracked falling to a quarter of capacity in its southern region — will be watching the Bay of Bengal for whatever the year still has left to give it, in a season most of the country will, by then, have already stopped paying attention to.
– Gangadhar Bolisetti
