An air quality ranking of 54 counties, cities, and districts in Jiangsu province for May was recently released by the Jiangsu Provincial of Department of Ecology and Environment, local media reported on June 22.

Haimen district's average PM2.5 concentration was 21 micrograms per cubic meter, ranking fourth among 54 counties, cities, and districts in the province, following Taicang city, Rudong county and Qidong city.

In addition, the proportion of days with good air quality in the district reached 74.2 percent, ranking fifth among 54 counties, cities, and districts in the province. Rudong county, which topped the list, was followed by Peixian county, Qidong city and Fengxian county.

Meanwhile, the proportion of days with good air quality in the district increased 19.4 percent, ranking first in the province.