Almost 78 percent of complaints the public made to the national environmental watchdog on its hotline in the first half of this year was about air pollution.

However, the authority needs to improve its services to deal more effectively with the complaints, some hotline users suggested.

The Ministry of Environmental Protection received 696 reports related to pollution on the hotline 12369 in the first six months of the year, the same number as in 2014, the ministry said on Monday.