Delhi No More The Most Polluted City in The World: WHO

Delhi is not the most polluted city in the world any more, according to the World Health Organisation’s (WHO) urban air quality database released on Thursday.
Totally, four Indian cities are among the world’s ten most polluted cities, 10 out top 20 are also in India. In WHO’s 2014 report, 13 out of 20 most polluted cities were in India.
Zabol in Iran is the most polluted city in the world according to the database. Gwalior and Allahabad are a close second and third in terms of PM 2.5, which is associated with more serious health impacts than PM 10. Patna and Raipur rank 6th and 7th.
In fact, it now ranks 11th among 3,000 cities in 103 countries in terms of PM 2.5 (fine, particulate pollution) and 25th in terms of PM 10 (coarse pollution particles) levels. This is though a considerable improvement since 2014 when Delhi was ranked the most polluted city in terms of PM 2.5 levels, WHO had monitored only 1600 cities last time. This time 1400 more cities have been included in the database.
WHO used data from various government and research organisations for the database, it’s based on ground measurements of annual mean concentrations of particulate matter (PM 10 and PM 2.5) and “aims at representing an average for the city or town as a whole, rather than for individual stations. Years of measurements range from 2010 to 2015, unless the latest available data was older,” the report said.
“Delhi has improved. Ahmedabad has stabilized and Patna has worsened.
“I am not surprised that four Indian cities are in the top ten list. In 2014, 13 out of top 20 cities were from India,” said Sunil Dahiya, campaigner with Greenpeace India.
World Top 20 polluted cities-2016 (WHO)
Country                City                       PM 2.5 Annual Mean (microg/m3)
Iran                       Zabol                     217
India                    Gwalior                  176
India                    Allahabad               170
Saudi Arab          Riyadh                   156
 Saudi Arab         Al jubail                 152
India                      Patna                    149
India                       Raipur                 144
Cameroon          Bamenda                132
China                   Xingtai                   128
China                  Baoding                 126
India                      Delhi                     122
India                    Ludhiana                122
Saudi Arab        Dammam                 121
China              Shijiazhuang              121
India                  Kanpur                      115
India                 Khanna                       114
India                Firozabad                    113
India                  Lucknow                    113
China               Handan                        112
Pakistan          Peshawar                     111