Beijing has strengthened environmental inspections and levied fines of over 34 million yuan on companies that pollute, an increase of 160 percent year-on-year, the municipal environment authority said on Monday.

In the first quarter, environmental authorities in the capital investigated 809 companies for pollution violations, double the number in last year's first quarter, and the total fines on polluters soared to 34.7 million yuan ($5 million), said Zhao Zhiwei, head of the municipal environmental inspection team.

Among the massive violations, more than half (54.4%) were punished due to problems with air pollution, he said.

The environmental police squad, which was formed on Jan 18, has participated in strengthening joint inspections on companies.

Environmental and public security teams carried out joint inspections, and worked with investigators on 13 environment-related events, Zhao said.

"We have smoothed the processes, such as in collecting evidence, making our collaboration more efficient," he said.

In the first quarter, public security authorities detained 46 people accused of committing crimes related to contaminating the environment.