* Daily steel output at record 2.7 mln T - Reuters calculation
* Average profit margins remain above 1,000 yuan/T - analysts
* Northern cities haven’t started enforcing winter curbs (Updates throughout)
BEIJING, Oct 19 (Reuters) - China’s daily steel output hit a record high in September, as mills in the world’s top producer rushed to cash in on strong profit margins before the start of winter production curbs aimed at tackling smog.
Crude steel production reached 80.85 million tonnes last month, up from August’s 80.33 million tonnes and well above 71.83 million tonnes in September last year, data from the National Bureau of Statistics showed on Friday.
September’s average daily output rose 4 percent from August to 2.7 million tonnes, the highest level on record, according to Reuters’ calculations based on NBS data. September had one day fewer than August.
“Mills have strong incentives to ramp up production due to hefty profits,” said Richard Lu, analyst at CRU in Beijing before the data was released.
The average profit margin at steel mills is currently running above 1,000 yuan ($144.16) a tonne, according to Huatai Futures.
For the first nine months of the year, steel output totalled 699.42 million tonnes, up 6.1 percent on the same period last year, the official data showed.
Cities in northern China have been ordered to curtail production during winter for a second year in a row as the country rolls out measure to reduce toxic emissions and curb choking smog.
The central government has ditched blanket cuts this year and will allow local authorities to set up production restriction plans on individual firms.
However, the more nuanced approach has spurred concerns about a potential increase in supply.
Steel mills in China’s top steelmaking hub Tangshan are boosting output as local officials delayed issuing precise orders on production curbs, even though the city kicked off its winter pollution campaign two weeks ago.
The blast furnace utilisation rate at steel mills across China rose last week to the highest level since July 20 at 68.65 percent, according to data compiled by Mysteel consultancy.
“There has been increasing uncertainties on steel supply this year, as on one hand northern China may adopt more lenient policies, but on the other hand, more regions in northwestern and southern regions could introduce winter restrictions,” said Lu. ($1 = 6.9369 Chinese yuan renminbi) (Reporting by Muyu Xu and Ryan Woo; editing by Richard Pullin)