“These acts of non-compliance with regulations are actually the result of lax supervision and weak law enforcement,” Cai told a government meeting.

Nearly three years into a “war on pollution”, large swathes of northern China were engulfed in smog over the New Year, with dangerous air quality readings in major cities like Beijing, Tianjin and Xian forcing many people to stay in doors.

The smog which blanketed cities, disrupting flights, port operations and schools, was caused by increased coal use for winter heating and unfavourable weather conditions.

The central government has promised to make greater use of police and law courts to prosecute companies and local officials responsible for exceeding emissions limits.

But while China’s environmental legislation has been beefed up in recent years, authorities have long struggled to build up the staff required to enforce laws.

China’s continuing reliance on fossil fuels, especially in the north, made the fight against pollution difficult, China’s environment minister Chen Jining said on Friday.

He said the six provinces and regions hit hardest by smog over the last month, including Beijing, consume a third of the country’s total coal and emit around 30-40 percent of China’s major atmospheric pollutants, despite accounting for just 7.2 percent of China’s total area.

But he said China would still be able to solve its pollution problems faster than western countries, including Germany.

“They needed 20-40 years to solve it. I believe we will do it faster than they did,” Chen said, according to a transcript posted on the State Council’s website. “We shouldn’t lose confidence because of a few days of heavy pollution,” he added.

China last week announced it would plough 2.5 trillion yuan ($361 billion) into renewable power generation by 2020.