4.1  Asia
From Fig. 1, Fig. 2 , the most polluting capitals of Asia are presented. At a general level, 27% of the capitals had a tendency to decrease the PM2.5 emission during Qut, however, the cities Kathmandu, Hanoi, Jakarta, Singapore and Tokyo had a tendency to increase the PM2.5 concentration by 11%. It should be noted that Tokyo, with the exception of the other cities, did not present a mandatory quarantine but as an option of the Government, they requested non-mandatory teleworking. For the analyzed Asian capitals, Dhaka in typical times (BQut), is the capital with the highest PM2.5 particles pollutant, registering a weekly average of 183 μg/m3. This capital city, presents a reduction of 24% in the Qut period. Delhi, with a weekly average of 140 μg/m3, has the highest reduction in particles polluting compared to other Asian countries, presenting a 40% reduction during Qut week. Capital cities with an average concentration of 121.91 μg/m3 (Kabul, Ullabantar and Kuwait City) show average reductions of 33% BQut. However, Bejing shows a lower reduction of 8%. Capital cities with an average concentration of 106.83 μg/m3 (Kabul, Colombo and Tashkent) show average reductions of 28%. Tehran has a typical week concentration of 90 μg/m3. However, its reduction during the quarantine week was 39%. Finally, Astana, with an average weekly concentration of 61.25 μg/m3, reduced its concentration by 18% during the Qut season.
Fig. 1 Capital cities Ankara, Astana, Bangkok, Beijing, Colombo, Delhi, Dhaka, Kabul and Hanoi, PM2.5 levels before and during quarantine (WAQ Index, 2020).
Fig. 2 Capital cities Jakarta, Kathmandu, Kubait city, Ulaanbaatar, Tashkent, Tehran, Tel Aviv, Tokio and Singapore PM2.5 levels before and during quarantine (WAQ Index, 2020).