October 2025: Challenging month for Delhi’s air and weather

October proved to be a tough month for Delhiites, as the city’s air quality not only deteriorated but also set several new records. According to Central Pollution Control Board (CPCB) data, October 2025 was the second most polluted October in the last five years. The average air quality index (AQI) for the month was 224, which puts it in the ‘poor’ category.

Although this figure is slightly better than last October’s 234, it is higher than the AQI levels recorded in 2023 (218), 2022 (210) and 2021 (173).

Despite this, the CPCB noted that significant rainfall helped control both temperatures and pollution levels. October 2025 proved to be the coldest October in the last three years, with rains preventing pollution from worsening. Experts say that without this rain, Delhi’s air quality could have deteriorated even faster.

The average maximum temperature for the month was 31.5°C, below the normal average of 33°C. The last time the maximum temperature in Delhi was 31.4 degrees Celsius in October 2022. Several days of rain in the first week kept the air relatively clean, but conditions changed after October 12, when dry weather and rising emissions took the AQI from poor to very poor, a trend that continued till Diwali.
It is not stubble burning but local pollution that is the main culprit.

According to Anumita Roychowdhury, executive director of the Center for Science and Environment (CSE), the decline in air quality during October was largely due to local pollution sources. He said stubble burning contributes only 1-2% to pollution levels, underlining that the main causes are within the city – vehicle emissions, construction dust and industrial pollution.

“It is necessary to control these local sources if we want clean air,” he told News18 Hindi.

Dipankar Saha, former head of CPCB’s air lab, said poor AQI levels are common at this time of the year due to low wind speed and weak ventilation, which traps pollutants close to the ground. “This does not mean that we should become careless,” he told News18 Hindi. “It is important to reduce emissions to reduce toxic chemicals in the air.”

October weather by numbers

• Rain: 90 mm – a remarkable 492% more than normal (15.1 mm).
• Comparison with last year: No rainfall was recorded in October 2024.
• Western Disturbance: Light drizzle in the final week added to the unusually wet conditions of the month.