China daily steel output rose in January and February, as mills in the world’s top producer ramped up production amid firm steel margins and easier environmental restrictions.

Average daily steel output over the two months reached 2.54 million tonnes, up from 2.46 million tonnes in December and 2.32 million tonnes in the same months last year, according to Reuters calculations based on official data.

The National Bureau of Statistics, which released the figures on Thursday, only provides combined output data for January and February to smooth the impact of the timing of the Lunar New Year holiday, which fell in early February this year.

Total steel output for the two months reached 149.58 million tonnes, up 9.2 percent from a year earlier, the official data showed.

The production pick-up followed a rise in profit margins at steel mills over January and February, with earnings from making construction product rebar jumping more than 20 percent from December, according to data tracked by Jinrui Futures.

Benchmark rebar prices on the Shanghai Futures Exchange have climbed 10 percent in the past two months and hit a peak of 3,908 yuan ($582.82) a tonne on Feb. 11, the highest level since late August.

Mills also took advantage of a change in winter anti-pollution restrictions after Beijing ditched blanket production cuts on heavy industry due to rising worries about slowing economic growth. Local authorities were instead allowed to adopt measures based on regional emission levels.

Output in March, however, is likely to be curbed due to more stringent pollution curbs in northern China. Air pollution in 39 smog-prone northern Chinese cities soared in February, a Reuters analysis of official data showed.

The cities of Tangshan and Wu’an in the major steel-making province of Hebei have already stepped up production restrictions on heavy industry for March.

Weekly utilisation rates at steel mills across China fell to 62.98 percent last week as of March 8, the lowest level in a year, data compiled by Mysteel consultancy showed.