BEIJING — Beijing has issued a yellow alert for heavy air pollution that took effect from 3 pm on Jan 24, local authorities said.

A series of measures will be taken from Jan 24, including the suspension of a number of outdoor construction operations, and halting or restricting production by manufacturing companies, according to the municipal air pollution emergency response office.

The capital's air quality is expected to gradually improve on Jan 26.

Under China's four-tier warning system for air pollution, red is the most severe, followed by orange, yellow and blue.