In 13 cities in the Beijing-Tianjin-Hebei region, "good air" days accounted for 64.5 percent of the total last month on average, up by 28.3 percentage points from a year ago, the statement said. Beijing saw the biggest improvement as the proportion of days with blue skies reached 80.6 percent.
The average density of PM2.5 in Beijing stood at 34 micrograms per cubic meter in January, dropping by 70.7 percent year on year, while the average level of PM10 was 64 micrograms per cubic meter, down by 51.1 percent from the same period last year.
No serious air pollution was registered in Beijing last month, the ministry said.
Nationwide, the 338 cities monitored by the ministry reported good air quality on 68.6 percent of the days in January, up by 8.6 percentage points year on year.
Provinces around Beijing are home to major steel-makers, coal mines, aluminum producers and chemical plants. They are also at the forefront of the country's fight against air pollution.
Local governments have slashed steel capacity, shut down illegal polluting factories, gradually ditched coal-burning heaters and curbed car emissions to reduce pollution.
An air pollution plan issued by the State Council in September 2013 ordered Beijing to reduce its PM2.5 density from 90 micrograms per cubic meter in 2013 to around 60 micrograms per cubic meter by the end of 2017.
In 2017, the average density of PM2.5 in Beijing was 58 micrograms per cubic meter thanks to effective pollution controls and favorable weather.