Fog in March is as unheard of as snow in summer. March is the month for palash (flame of the forest) to burst into bloom, for wheat to ripen as it soaks up the sun. This year though, March has been markedly different, even frightening.

In the first week, a dense fog descended on Delhi, Ghaziabad, Kanpur and Lucknow; a Delhi-Ranchi flight was diverted to Kolkata because of fog affecting visibility. Sweaters and woollens were brought out in some places in western Uttar Pradesh. When ground visibility became zero, it became clear that the balance of nature had been severely disrupted. Seasons were no longer following familiar patterns. To top it all, sudden rain and hailstorms destroyed standing crops.

Meteorologists described it as a climate emergency. Fog typically forms on winter nights when the earth rapidly releases heat and humidity levels are high. This year, the heatwave that began abruptly in the last week of February shattered all records. The Earth’s surface overheated. When moisture-laden easterly winds from the Bay of Bengal came into contact with this overheated surface, and the night temperature suddenly dropped by six to seven degrees, a dense blanket was formed. In scientific terms,........

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