BEIJING -- China's environmental watchdog said on Thursday that air pollution ranked as the biggest source of complaints among the 149 tip-offs it dealt with in June.

Of the processed tip-offs, 120 were about environmental illegalities, accounting for 81 percent of these reports, according to the Ministry of Environmental Protection.

The environmental watchdog in North China's Hebei province received 29 such tip-offs, the highest number of complaints. It was followed by the provinces of Shandong, Jiangsu and Henan, said the ministry in a statement.

Among the 10 most-heavily polluted cities, seven are in Beijing-encircling Hebei province, the ministry said earlier this month.

Seventy-eight of the total 164 tip-offs on environmental pollution received by the ministry in June were about air pollution, 29 about water pollution, 23 about noise pollution, three about solid waste pollution and 31 were about projects not properly approved.

In 32 cases, businesses were suspended to allow for pollution control. In 27 other cases, businesses were fined. Still in 21 cases, projects were canceled or businesses were closed.

In Southwest China's Guangxi Zhuang autonomous region, a fertilizer production company was ordered to stop production and not to resume until it has built necessary pollution control facilities.

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