Mumbai in top ten polluted cities

Six of the top 10 cities fall in the Indian sub-continent -- Delhi, Lahore, Karachi, Kolkata, Mumbai and Kathmandu.

Delhi has earned the dubious distinction of becoming the most polluted city in the world with an air quality index (AQI) of 527 on Friday, as per data released by Air Visual on the World AQI rankings.

Delhi air quality broke all records on November 5, when it was in the hazardous range for nine consecutive days, making this the longest spell of hazardous air quality since public records are being kept, according to Air Visual.

Six of the top 10 cities fall in the Indian sub-continent -- Delhi, Lahore, Karachi, Kolkata, Mumbai and Kathmandu. So within Asia, air pollution is concentrated in South Asia.

Three Indian cities are in the list -- Delhi, Kolkata and Mumbai. So, air pollution is not necessarily a problem specific to northern India, although Delhi's pollution is double that of Kolkata.

Delhi's air pollution has been making international headlines and while India endeavours to become a global super power, the state of air pollution in the national capital is ticking all the wrong boxes for global tourists, investors and international perception of India.

As per the world AQI rankings, Delhi is followed by Lahore in Pakistan at 234. However, there is a huge gap between the two and Delhi is suffering more pollution with a difference of more than two times. At third spot is Tashkent in Uzbekistan at 185 count which is a surprise because it is in a region considered to be not so congested and polluted.

Pakistan port city Karachi is at the fourth place with an AQI count of 180, followed by Kolkata at 161 in the fifth place. China marks its entry with Chengdu with an AQI of 158.

Hanoi in Vietnam with an AQI of 158 is at the seventh spot followed by Guangzhou in China with an AQI of 157. India's financial capital, Mumbai, is in the ninth place with an AQI of 153 and the dubious Top 10 concludes with Kathmandu in Nepal at 152.