Air pollution has reached hazardous levels in the Indian capital, Delhi, after many firecrackers were set off to celebrate the festival of Diwali at the weekend.
People celebrated the festival on Sunday night with colourful fireworks across the city, but woke up the next morning to find the city covered in a thick grey blanket of smog.
The situation hasn't changed much since then. The Indian Meteorological Department said Wednesday recorded the worst smog and visibility in 17 years.
Levels of tiny particulate matter (known as PM 2.5) that enter deep into the lungs reached as high as 800 micrograms per cubic metre in the past four days, data from the Delhi Pollution Control Committee showed.
That is 30 times a mean guideline set by the World Health Organisation (WHO) of 25 micrograms per cubic metre on average over a 24-hour period.
Anumita Roychowdhury of the Centre for Science and Environment said the situation "demands emergency response".
"The government should aggressively inform all and advise them to stay indoors and avoid outdoor exercises," she said.
The BBC spoke to some Delhi residents about how they were coping with such alarming levels of pollution.
Aryamaan Sen: 'Cant play football'
I am 11 years old and I love to play football like most of my friends. But I haven't been able to play properly since Sunday. I feel tired and breathless in 20 minutes and then I just go back to my house.
My friends feel the same. We feel we have no stamina left.
Earlier, we could play for hours without any problem. We are thinking that we should stop playing outdoors completely until the air becomes better.
It's so sad. Why do people set off fireworks? We don't need them. People need to know that our health is more important than fireworks. Please stop this madness.
Mahendra Sharma: 'Diwali is about peace, not pollution'
I have been an auto-rickshaw driver for more than 20 years but this is the first time I have seen such thick smog after Diwali. I am 55-years old and I cannot take such pollution at this age.
The government forced us to use compressed natural gas (CNG) for tuk-tuks to reduce pollution. I find it so ironic that we use greener fuel, but suffer the most due to pollution.
Tuk-tuks are open and that is why I have been literally breathing smog since Diwali. My eyes itch and I frequently feel breathless. But I can't rest because I have to earn every day for my family.
I hope people stop setting off fireworks. It is a relatively new phenomenon, we only used to have lamps earlier. Diwali is about peace, not pollution.
Shilpa Kannan: 'Not all of us can run away from here'
It's sad when parents make WhatsApp groups to discuss which are the best face masks for children. We are talking about six year olds here.
Schools are curtailing sports activities. Many friends are taking sudden vacations to get out of Delhi and escape the pollution. But not all of us can run away from here.
So to cope with the pollution, we wear masks when outside. Keeping our doors and windows shut and using multiple air purifiers at home helps to a certain degree.
Even with all these precautions, many children, specially those facing breathing problems or persistent coughs, need daily nebulisation.
I haven't been able to send my two sons out to play since Diwali.
Shilpa Kannan is a BBC journalist
Nishank Dadu: 'Fireworks are not cool'
I am a businessman and I have to meet several people every day. But I have consciously tried to not go out much because of the smog since Diwali.
I feel breathless even inside my car. I can't keep the windows of my house open. Delhi has become a gas chamber and nobody seems to be doing anything to improve the situation.
We as a family don't set off fireworks and request other people to do the same, but then not many listen.
I am thinking of buying air purifiers for my office and home, but that's not a permanent solution. People really have to understand that we have made the city a ticking time bomb.
But fireworks can't be blamed as the main contributor to pollution. Vehicle emission, dust coming from construction sites and smoke coming from burning of crop stubble in farms all contribute to Delhi pollution and the government needs to have a strict policy to deal with these issues.