Delhi is currently in the grip of a heatwave, recording an unusually warm morning on September 29, 2025, with temperatures rising to 28.2°C. This is five degrees above the normal, making it the hottest September morning in six years. A similar temperature was recorded on Sunday, indicating persistently warm nights at a time when conditions are expected to ease. The last time Delhi experienced a higher minimum temperature in September was in 2019, when 29.6°C was recorded on September 12.

The daytime heat in the Capital offered no relief either. On Sunday, Delhi recorded a maximum temperature of 38.1°C,  three degrees above normal and the hottest September day in two years. The last time the city saw higher daytime heat in this month was on September 5, 2023, when temperatures touched 38.6°C.
Reason behind the rise in temperature.

The current hot spell is largely due to the absence of rain-bearing systems. The Southwest monsoon withdrew from Delhi on September 24, its earliest retreat since 2002. Despite Northwest India receiving 42% surplus rainfall this September, Delhi continues to sizzle, according to a report by The Indian Express.

With no cloud cover, clear skies allow intense daytime heating. At night, high humidity is preventing temperatures from dropping. Relative humidity stayed between 56% and 76% through the day, trapping heat near the surface like a blanket. Persistent easterly winds have kept moisture levels high, offering no night-time relief.

However, these winds, blowing at up to 20 kmph over the past 24 hours, have helped maintain better air quality by blocking smoke from farm fires in northern states. According to data from the Indian Agricultural Research Institute (IARI), 130 cases of stubble burning have been reported so far this season. Out of these, 90 were in Punjab, 27 in Uttar Pradesh, 6 each in Haryana and Madhya Pradesh, and 1 in Rajasthan.

Every year, Punjab and Haryana are blamed for the rise in Delhi’s air pollution after paddy harvesting in October and November. However, this year, stubble burning has started earlier, from around September 15, and has already started affecting Delhi’s air quality.

On September 29, 2025, the first FIR of the season was filed against a farmer in Dera Bassi (Mohali) under Section 223 for burning crop residue, as reported by news agency PTI. On Sunday, Delhi’s 24-hour average Air Quality Index (AQI) stood at 139 (“moderate”) at 4 pm. This was slightly better than Saturday’s AQI of 169, which was also the city’s highest reading since June 13.