The joy of Diwali lights and sweets has quickly turned into a nightmare for people in Delhi and Bihar. On October 21, 2025, just a day after the festival on October 20, the air in these areas has become very bad. In Delhi, the Air Quality Index or AQI has gone above 400 in many places, putting it in the ‘severe’ category. This means the air is so dirty that it can make even healthy people sick. In Bihar, cities like Patna are seeing AQI over 300, which is ‘very poor’. Firecrackers burst during Diwali night are a big reason, but bad weather and smoke from farms in nearby states are making it worse.
Millions of people are now facing trouble breathing, sore eyes, and coughs. The government has started emergency steps, but experts say this problem comes back every year and needs better long-term fixes. Let’s look at what happened, why it’s so bad, and what you can do to stay safe.
Delhi’s Air Turns Toxic Overnight
Delhi woke up to a thick layer of smog on Tuesday morning. The Central Pollution Control Board (CPCB) said the average AQI was around 420 by 8 AM, which is severe. But on Diwali night, it was even worse – hitting 596 at 11 PM in some areas. That’s like breathing poison! Many people ignored the rules against firecrackers, and the smoke from them filled the air with tiny particles called PM2.5 and PM10. These particles are so small they can go deep into your lungs.
Anand Vihar, a busy area in Delhi, recorded AQI of 480, while places like Jahangirpuri hit 450. Residents say they could hardly see across the street because of the haze. “I stepped out for a walk and felt like my throat was on fire,” said Rajesh Kumar, a shopkeeper in south Delhi. This is not new for Delhi, which often has the world’s worst air in winter. But this post-Diwali spike is one of the bad ones in recent years.
Experts blame the fireworks for adding extra pollution on top of the usual dust from roads, cars, and factories. “Firecrackers release harmful gases like sulfur dioxide and nitrogen oxide, which mix with the air and create more toxins,” explained Dr. Arvind Kumar, a lung specialist at a Delhi hospital.
Weather Makes It Worse
It’s not just the firecrackers. The weather is playing a big role too. The India Meteorological Department (IMD) said on October 21, the temperature in Delhi would be about 31 degrees Celsius during the day and 22 degrees at night. There was light fog in the morning, which traps the dirty air close to the ground. Winds are slow, only 5-10 km per hour, so the pollution doesn’t blow away.
IMD forecasts say the air might get even dirtier in the next two days because of calm winds and cooling temperatures. This creates something called a ‘temperature inversion’ – like a lid on the city that keeps the smog in. “With no rain and slow winds, the pollutants just hang around,” said a senior IMD official. People in Delhi-NCR can expect dry weather with some sun in the afternoon, but no real relief until maybe the weekend.
Government Steps In with GRAP
o fight this, the Commission for Air Quality Management (CAQM) has started Stage II of the Graded Response Action Plan (GRAP). This happened right away when AQI went into ‘very poor’ before Diwali, but now it’s even more urgent. Under GRAP Stage II, things like higher parking fees to reduce cars, no diesel generators except for emergencies, and more road cleaning to cut dust are in place.
The Delhi Pollution Control Committee (DPCC) is checking factories and construction sites to make sure they follow rules. “We are monitoring closely and will take strict action against those breaking the ban on firecrackers,” said a CAQM spokesperson. But many say these steps are not enough because the problem comes from outside Delhi too. Regular meetings are happening to review the situation.
The Bigger Problem: Farm Smoke and Cars
Delhi’s air trouble isn’t just from Diwali. Smoke from burning crop waste, called parali, in Punjab and Haryana is a big part. Farmers burn the leftover rice stalks to clear fields quickly, and the wind carries the smoke to Delhi. This year, there are fewer fires because of recent floods, but still hundreds of cases reported in October. “It’s their smoke,” said BJP leader Amit Malviya, blaming the Punjab government for not stopping it.
Cars and trucks also add a lot of pollution. With millions of vehicles on Delhi roads, the exhaust fumes mix with everything else. Experts like Anumita Roychowdhury from the Centre for Science and Environment (CSE) say, “We need better teamwork between states. Push for electric buses and cars, and give farmers machines to handle stubble without burning.” Without this, the winter smog will keep coming back.
Bihar’s Pollution Battle
The problem isn’t only in Delhi. In Bihar, cities are also covered in smog. Patna’s AQI crossed 300 on Tuesday morning, making it ‘very poor’. Places like Hajipur hit 304, which is severe. Gaya and Bhagalpur are around 250-280, poor category. Firecrackers from Diwali night left a lot of smoke, and slow winds of just 2-3 km/h aren’t helping it go away.
Temperatures in Bihar are mild – Patna had 24.7C minimum and 33.8C maximum recently. But the low wind keeps the dust and smoke trapped. “My eyes are burning, and I have a headache since morning,” said Sunita Devi, a homemaker in Patna. There’s some hope – IMD says a low-pressure area in the Bay of Bengal might bring light rain around October 25, which could clean the air a bit.
Bihar officials are telling people to wear masks outside. The state pollution board is watching closely, but like Delhi, the issue is from local sources like vehicles and some farm burning nearby.
Health Dangers and Advice
This bad air is very risky for health. When AQI is over 400, it can cause serious problems even for fit people. PM2.5 particles go into your blood and can lead to heart attacks, strokes, and lung diseases. Kids, old people, and those with asthma or heart issues are in more danger. “This is a public health emergency,” warned experts from NDTV.
Doctors say stay indoors if you can, use air purifiers, and wear N95 masks outside. Avoid exercise in the open air. “Drink lots of water and eat fruits to help your body fight the toxins,” advised Dr. Sundeep Salvi, a pollution health expert. Long-term, this air can shorten lives and make more people sick with COPD or cancer.
The crisis shows we need to celebrate festivals in a green way – maybe with lights but no crackers. Governments must work year-round on clean air plans.
Frequently Asked Questions (FAQs) on Air Quality Index (AQI)
Here are some common questions about AQI, answered in detail to help you understand better.
- What is the Air Quality Index (AQI), and how is it calculated?
The AQI is a simple number that tells you how clean or dirty the air is. It’s like a report card for the air. Government groups like CPCB use it to warn people. They measure pollutants like PM2.5 (tiny dust that can enter lungs), PM10 (bigger dust), nitrogen dioxide (from cars), sulfur dioxide (from factories), ozone, carbon monoxide, ammonia, and lead.
For each pollutant, they check the amount in the air over 24 hours or less. Then, they give each a score based on how bad it is for health. The final AQI is the highest score among them – so if one pollutant is very high, the whole AQI goes up. In India, the scale goes from 0 to 500+. Colors help: green for good, purple for severe. This way, even without knowing science, you can see if it’s safe outside.
- What are the different categories of the AQI scale and their associated health impacts?
The AQI has six main levels:
- 0-50: Good (Green) – Air is clean, no health worry for anyone.
- 51-100: Satisfactory (Yellow) – A bit dirty, but only sensitive people like asthmatics might feel slight discomfort.
- 101-200: Moderate (Orange) – People with lung or heart problems, kids, and elders may have trouble breathing if outside long.
- 201-300: Poor (Red) – Most people feel uncomfortable after hours outside; bad for sick ones.
- 301-400: Very Poor (Dark Red) – Can cause illness in lungs after long exposure; high risk for those with diseases.
- 401-500: Severe (Purple) – Hits everyone; can lead to serious issues like heart problems. Stay inside.
- Over 500: Severe+ or Emergency (Maroon) – Health crisis; all at risk, even indoors.
These levels help decide actions like school closures.
- Why does a ‘Severe’ AQI (like 400+) pose a significant health risk?
When AQI is severe, the air has too much PM2.5 – particles smaller than hair that slip past your nose and go straight to lungs or blood. This can inflame your body, leading to cough, wheezing, or worse like asthma attacks. For heart, it raises blood pressure and risk of attacks or strokes.
In places like Delhi, where this happens often, long exposure can cause chronic diseases, weaker immunity, and even early death. Kids’ lungs don’t grow well, and elders face more hospital visits. Visibility drops, causing accidents too. Health groups say avoid outdoors, seal windows, and use masks. “Severe AQI is like smoking packs of cigarettes a day,” said a WHO report on India. In emergencies, governments may declare alerts.
This article is based on latest data as of October 21, 2025. Stay safe and check AQI apps daily.