Tezpur is India's cleanest
Guwahati, Assam [May 2016]
Historic Tezpur is India's least polluted city, according to the
recently-released World Health Organisation's report.
Tezpur is followed by Pathanamthitta in Kerala and Hassan in Karnataka.
The study was conducted in 2,973 cities across the globe in 103 countries, including 122 in India.
As per WHO guidelines, the permissible limit in case of PM 10 is 20 g/m3 (micrograms per cubic metre of air) and PM 2.5 is 10 g/m3.
In Tezpur, the concentration of particulate matter (dust) with the annual mean PM 10 was found to be 11 g/m3 and annual mean PM 2.5 was 6 g/m3. Tiny particulate matter less than 2.5 micrometers in size are known as PM 2.5. These are thought to be the most deadly as they can find their way deep inside a person's lungs.
In Pathanamthitta, the annual mean PM 10 was 23 g/m3 and annual mean PM 2.5 was 12 g/m3, while in Hassan, the annual mean of PM 10 was 36 g/m3 and PM 2.5 was 19 g/m3.
According to the study, Delhi is no more the world's most polluted city. Gwalior, Allahabad, Patna and Raipur have overtaken Delhi in the latest WHO report released on Thursday.
Delhi is at the 11th spot among the 20 most polluted cities, with the PM 2.5 level recorded at 122. However, 10 of these 20 cities are in India.
Next in the updated WHO list are Gwalior and Allahabad (India), Riyadh and Al Jubail (Saudi Arabia), Patna and Raipur (India), Bamenda (Cameroon), Xintagi and Baoding (China) and Delhi and Ludhiana (India).
Gwalior's PM 2.5 level is 176, followed by Allahabad (170), Patna (149), Raipur (144), Ludhiana (122), Kanpur (115), Khanna (114), Firozabad (113) and Lucknow (113).
Topping the list of polluted cities is Zabol in Iran (217).
The annual mean of PM 2.5 in (g/m3) of New York and London is 9 and 15
Despite the dismal Indian standing, the sole consolation was that the number of Indian cities in the list of the world's 20 most polluted cities had come down to 10 from 13 in 2014.
Poonam Khetrapal Singh, the WHO regional director for Southeast Asia, said in a statement that increasing air pollution levels are putting the health of billions of people at risk.
"We have overwhelming evidence of the impact of air pollution on stroke, heart disease, lung cancer and chronic and acute respiratory diseases," Singh said.
WHO said that while all regions of the world are affected, populations in low-income cities have been the most impacted.
As per WHO, 98 percent of cities in low and middle income countries with more than 100,000 inhabitants, do not meet WHO air quality guidelines.
In high-income countries, that percentage falls to 56 percent.
Thirty four Indian cities figured in the list of the 100 most polluted ones, and 22 Indian cities found their names among the top 50 most polluted in the world.
Importantly, a majority of the most polluted cities in India are from the western and northern states. There is not a single city from the four southern states in the list.
The statement issued by WHO said, "Measurement of fine particulate matter of 2.5 micrometers or less in diameter is considered to be the best indicator of the level of health risks from air pollution." Indian cities account for one third of the100 most polluted cities in the world.
Courtesy: by VOA