BEIJING - The air in Beijing, as well as its surrounding areas, was heavily polluted in June, the Ministry of Environmental Protection (MEP) said Wednesday.

Up to 21.2 percent of the days in June saw air quality in Beijing, as well as neighboring Tianjin municipality and Hebei province, heavily polluted, according to MEP air quality readings for 74 cities and three city agglomerations.

Combined average air quality readings for the 74 cities met standards for over half the days in June. The Pearl River Delta, a city agglomeration in South China, had good air quality for nearly 90 percent of the days in June.

The air in Beijing, Tianjin and Hebei was heavily polluted for about one-quarter of the first half of the year, the worst of the three city agglomerations monitored by the MEP.