World’s most toxic cities today: South Asia leads with six

Delhi recorded the worst air quality in the country with its air quality index (AQI) dropping to the "severe" category for the first time this season on Wednesday, even as the central pollution watchdog attributed the deterioration to an "unprecedentedly dense" fog and described it as an "episodic event".

The city's 24-hour AQI, recorded at 4.00 pm every day, stood at 418, up from 334 the previous day, and may trigger stringent restrictions under the third stage of the Graded Response Action Plan (GRAP) to mitigate hazardous conditions. On average, Delhi is the second most polluted city and joins five more South Asian cities in the top ten list of...

...the most polluted cities in the world

1. Delhi, India

With an AQI of 686, Delhi on Thursday took over Lahore as the most polluted city in the world. The city's AQI has been a matter of concern for months now, with the NCR (National Capital region) and surrounding states like Punjab, Haryana and Uttar Pradesh implementing policies to minimise pollutants. Despite the decline in stubble burning — a traditional source of pollution — however, Delhi's air quality remains alarming.

2. Lahore, Pakistan

A few days ago, a Lahore shrouded in smog, with an alarming AQI of 1039, was the most polluted city in the world. Schools were shut until 17 November, and Pakistan Punjab's provincial government ordered a complete ban on people's entry to public and private parks, zoos, playgrounds, historical places, monuments, museums and similar establishments. Lahore's AQI has crossed 1,000 more than once.

3. Dhaka, Bangladesh

Dhaka's 'unhealthy' air quality with an AQI of 213 makes it the third most polluted city. According to Berkley Earth, breathing the air in the city is as harmful as smoking 3.4 cigarettes a day, as the citizens are put at a high risk of asthma.

4. Kolkata, India

Kolkata's AQI of 242 places the city in the 'unhealthy' category. Thus, Kolkata is one of many Indian cities with alarmingly bad air quality.

5. Hanoi, Vietnam

Hanoi's AQI of 177 ranks among the cities with the highest AQI levels in the world. Marked 'unhealthy', people are advised to avoid exercising outdoors, and closing windows to avoid dirty outdoor air.

6. Jakarta, Indonesia

With an AQI of 158, the city's air is deemed 'unhealthy'. According to the Jakarta Post, the Jakarta Environment Agency has installed more air quality monitoring stations in an effort to curb air pollution in the city.

7. Kathmandu, Nepal

Nepal's capital has an AQI of 155, marking the city's air 'unhealthy'. Despite being surrounded by lush green mountains, the landslide-prone city has forced its people to wear masks while stepping outside.

8. Sarajevo, Bosnia

Sarajevo's AQI is marked at 158, and deemed unhealthy for sensitive people. The city's PM2.5 concentration is 10.3 times the World Health Organization's annual PM2.5 guideline value.

9. Mumbai, India

Mumbai's AQI of 154 makes it the third major polluted Indian city.

10. Dubai, United Arab Emirates

At 129, Dubai's AQI is denoted to be 'unhealthy for sensitive groups.' However, the immigrant labourers building this city of skyscrapers are more vulnerable to the heat, humidity and poor air quality, which result in several illnesses and even fatalities.

According to Swiss climate group IQAir, poor air quality in South Asia is a result of “brick kiln and other industrial emissions, agricultural waste burning, and cremation practices”. It is also imperative to note that South Asian countries focus on development and prioritise industries that aid the economy, rather than the growth and holistic wellbeing policies pursued by developed countries.