Air pollution: Schools in Delhi shut as air quality levels reach 'severe'

Image source, RAJAT GUPTA/EPA-EFE/REX/Shutterstock

Image caption, Indian school children can be seen here wearing face masks to protect themselves from the air pollution in the city

Air quality in India's capital city Delhi has become so poor that the government has ordered all primary schools to shut until 10 November.

It's the first time this season the air quality level has dropped to 'severe'.

The pollution levels in the city reached 450 on the World Health Organisation's (WHO) air quality index, which measures how much PM 2.5 - or fine particulate matter - there is in the air.

The latest measurements of pollutants are nearly 10 times the acceptable limit.

Video caption, What's air pollution and why's it so important?

Polluted air causes severe health issues to people living in Delhi every year.

Health professionals are reporting increasing cases of asthma and lung issues among children and the elderly because of the worsening air quality.

People who have issues with their breathing have been encouraged to stay indoors.

Image source, Getty Images

Image caption, Polluted air causes severe health issues to Delhi residents every year

Why is Delhi's air pollution so bad?

Delhi is one of the most polluted areas in the world, and the air quality gets particularly bad in winter.

There are a number of reasons for this - one is that during the first two weeks of November many farmers burn their crop remains - adding to the pollutants in the air.

Image source, Hindustan Times / Getty

Image caption, Firecrackers are a big part of Diwali celebrations in Delhi, but this year they'll be banned in the city

Another cause is low winds speeds, so any air pollution lingers longer than at other times of year - it doesn't get blown away.

There are also many festivals taking place, such as Diwali, where fireworks are usually set off.

How are is Delhi's government trying to tackle the problem?

Delhi's environment minister has called an emergency meeting to review the situation, but there are some plans already in place.

All non-essential building work in the city was ordered to stop for the time being.

Image source, Getty Images

Public transport such as trains and buses have been made more frequent to discourage people from driving.

And last month, a ban on firecrackers being let off in the city was put in place.