BEIJING - Over 500 illegal barbecue grills in Beijing were destroyed on Tuesday amid the city's efforts to fight air pollution and lingering foggy weather.

Beijing Municipal Bureau of City Administration and Law Enforcement started an operation in August to supervise the capital city's open-air barbecues, which cause serious air pollution and contribute PM 2.5 particles, authorities with the bureau said. PM 2.5 are airborne particles measuring less than 2.5 microns in diameter, which can pose health risks.

Over 500 illegal barbecue grills have been seized during the three-month operation, according to authorities.

In its battle for blue skies, Beijing has adopted an emergency response program to allow cars with odd and even license plates on roads on alternating days and to close schools when a "level one" alert is issued. The city also started a pilot air quality warning system on November 1 that will issue different warning levels, with a level one alert issued when the air quality index goes beyond 500.

According to an action plan unveiled in September, inhalable particulate matter will be cut by at least 10 percent in major cities nationwide by 2017. In Beijing and its environs, PM 2.5 should fall by about 25 percent from 2012 levels by 2017.