Emergency measures have been introduced in the South Korean capital of Seoul to combat a thick layer of smog that is covering the city.

Public transport is free during rush-hour as of Monday 15 January, in the hopes that car use will be reduced.

The measures were introduced after the average daily density of ultra-fine dust hit more than 50 micrograms per cubic metre, an amount that is considered harmful.

South Korean officials used the same tactics for the first time last year when Seoul’s air quality index reached levels in excess of 179 micrograms per cubic metre. This put it only behind New Delhi in India in terms of air pollution.

Seoul’s poor air quality is thought to be a result of the country’s use of coal and diesel, compounded by smog from nearby China.

Other measures to reduce the current levels of air pollution include limitations of car use for public employees, the closure of 360 parking lots and a reduction in construction work on government-funded projects.

All policies should only be in place for a few days.

This comes after The Independent reported in November 2017 that New Delhi announced a ban on lorries after high levels of air pollution triggered a public health emergency.

The Indian capital was cloaked in thick smog, forcing thousands of schools to close.

Levels of PM2.5 pollutants in New Delhi hit 1,000mg; to put this in context, 300mg is considered a highly dangerous amount. Pollution levels in the city had therefore reached 30 times higher than the World Health Organization considers safe.