BEIJING — Beijing saw its primary air-pollution index reading fall 28.3 percent year-on-year in the first five months of 2022, official data showed on June 22.

The city's average concentration of PM2.5 was 33 micrograms per cubic meter in the January-May period, said the Beijing Municipal Ecology and Environment Bureau. The reading in May was 21 micrograms per cubic meter.

The readings of PM2.5, PM10, nitrogen dioxide, and sulfur dioxide were all at the best levels for the same five-month period over the years since records began in 2013, the bureau said.

PM2.5 readings are a gauge monitoring airborne particles of 2.5 microns or below in diameter.

Local authorities in the city have taken a spate of measures to tackle air pollution this year, including strengthening pollution treatment at industrial companies and promoting new energy as well as new-energy cars.

Beijing made a breakthrough in its air pollution control last year as the city reached the national air quality standard. The city's average concentration of PM2.5 was 33 micrograms per cubic meter in 2021, the lowest level since records began in 2013.