Despite pledges in the last year to fight pollution, Beijing saw barely any improvement in air quality in 2013.

The intensity of major air pollutants remained much the same in 2013 as they were in the previous year, figures released by the Beijing Environmental Protection Bureau on Thursday indicate.

PM2.5, airborne particulate matter smaller than 2.5 micrometers in diameter, was 2.5 times the national standard, it said.