NANJING -- East China's economic powerhouse Jiangsu province reported a record-low average PM2.5 density, a key indicator of air pollution, in 2022, local authorities said.

The average concentration of PM2.5 in Jiangsu was 31.5 micrograms per cubic meter in 2022, down 3 percent year on year, marking a nine-year straight decline since the data was first collected in 2013.

The rate of good air quality days in Jiangsu reached 79 percent in 2022.

Data also showed that the density of PM10 and nitrogen dioxide in Jiangsu last year dropped by 7 percent and 13.8 percent, respectively.

Compared to five years ago, the PM2.5 density decreased by 31.9 percent and the rate of good air quality days rose 4.6 percentage points in Jiangsu.

The province has set the targets for environmental protection this year, including keeping the PM2.5 density at around 32 micrograms per cubic meter and raising the rate of good air quality days by 1 percentage point.

The PM2.5 reading monitors airborne particles of 2.5 microns or less in diameter, which can penetrate deep into people's lungs.