SHANGHAI, Aug 28 (Reuters) - The major steel-producing city of Tangshan ranked as China's most polluted in July, even after ordering its mills to cut output in the last 10 days of the month, data from the environment ministry showed.
Average concentrations of hazardous airborne particles known as PM2.5 reached 42 micrograms per cubic metre in Tangshan, slightly lower than the same period last year but still the highest in the country.
The average across 337 monitored cities stood at 20 micrograms, unchanged from a year earlier, with 155 cities meeting China's national 35-microgram standard over the period, the Ministry of Ecology and Environment said on Tuesday.
However, concentrations of ground-level ozone, known as "sunburn for the lungs" and caused by the interaction of car exhaust fumes with sunlight, rose 8.1% compared with a year earlier.
Tangshan is in Hebei province, China's top steel-producing region that surrounds the capital, Beijing.
The province's crude steel output fell 11.8% to 18.9 million tonnes in July as a result of the curbs but production in other sectors, such as autos, batteries and solar panels, surged over the month, according to the provincial statistics bureau.
Tangshan is expected to face stricter production cuts in September, with Beijing desperate to minimise smog throughout northern regions as it celebrates the 70th anniversary of the establishment of the People's Republic of China on Oct. 1.
(Reporting by David Stanway Editing by Paul Tait)