China has just faced its smoggiest March in 52 years, announced the China Meteorological Administration (CMA) on Tuesday.

Nationwide, an average of 3.3 smoggy days were registered in March, 1.1 days more than the same period in normal years, the CMA said.

Meteorologists attributed the record to ridges of high pressure that took control of the weather in most parts of the country.

There was no strong wind to disperse the smog, said Chen Zhenlin, an official from the CMA.

Since the beginning of this year, smog has engulfed large areas of China on 10 occasions, mostly in its central and eastern regions. The polluted air usually lingered for more than three days. It stayed for up to 15 days in some areas.

The air pollution reduced visibility on roads and led to a surge in respiratory illnesses, particularly among children and the elderly.

The causes of the smog are rather mysterious, though experts continue to cite excessive emissions and terrain conditions that trapped pollution when there was no ample wind to clear it.