Delhi's air quality drops on Diwali day; world's most polluted city, shows index

Delhi’s air quality dropped to the “very poor” category this Diwali morning (October 24), even as a global air quality index, AQI, measured by Switzerland’s IQAir, showed that Delhi is the most polluted city in the world right now. Pakistan’s Lahore is the next most polluted city.

Delhi’s AQI stood at 301 at 8 am today. An AQI between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

The day before Diwali on October 23, the national capital showed a 24-hour average AQI of 259 and this was the lowest very recorded in Delhi on this day in the past seven years.

However, unfavourable meteorological conditions which facilitated the accumulation of pollutants, coupled with emissions from firecrackers and crop residue-burning has aggravated the situation, said news reports.

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Pollution levels increased overnight after temperature and wind speed dropped and people burst firecrackers in several parts of Delhi. PM2.5 level currently is almost 400 micrograms per cubic metre close to Greater Kailash in south Delhi, which is 80 times the World Health Organisation’s safe limit of 5 micrograms (annual average).

The World AQI website shows India in the second spot after Qatar as having the most polluted cities. This index also includes Delhi. Delhi Chief Minister Arvind Kejriwal, however, in a tweet stressed that Delhi is not in the 10 most polluted cities list in Asia, which includes eight from India.

Delhiites woke up to a pleasant Monday morning with the minimum temperature settling at 14.9 degrees Celsius, two notches below the seasons average.

The relative humidity at 8.30 am was 82 per cent. The weather department had forecast mainly clear sky for the day with the maximum temperature likely to settle around 31 degrees Celsius. However, pollution levels crept up at night amid a drop in temperature and wind speed as people burst firecrackers in several parts of the national capital and the number of farm fires rose to 1,318, the highest this season so far.

The city on Sunday recorded a maximum temperature of 31.2 degrees Celsius, one notch below the average, while the minimum temperature settled at 14.5 degrees Celsius.