The smog here was so thick,

drivers couldn't see where they were going.

At least 24 vehicles were damaged

as drivers kept crashing into the pileup.

These conditions happen every year,

when Delhi experiences a huge spike in air pollution.

“Are we breathing poison in Delhi?”

“...every two minutes one person dies due to air pollution in this country.”

“I get nauseous.

I get dizzy.”

" I have to go to the hospital or the doctor now."

When it hits, the nearly 30 million people

here are forced to live in a toxic cloud.

Scientists estimate that spending a day outside

in these conditions is like smoking 50 cigarettes.

“As a lung surgeon, when I open the chest

I rarely see a normal pink lung these days.”

On the ground, a layer of dust covers the entire city,

and, in the air, a thick layer of pollution hides landmarks

that are easy to see the rest of the year.

Delhi has always been a big, busy, polluted city.

But in the last decade something is making

it even worse.

In the last 10 years, Delhi's population

has grown by more than 7 million people.

Today it's the second-largest city in the world

and it's also among the most polluted.

More people means more cars,

spreading dust and exhaust into the air.

As Delhi grows, there's also more construction,

producing dust particles.

And more industries, contaminating the environment.

All these things make  the average air quality in Delhi

unhealthy year-round.

But something else is happening right here,

when air pollution in Delhi spikes

in October and November.

It sends air pollution levels to

fifty times what's considered safe.

“Levels go haywire.

Many of the machines are not made

to measure the levels that we achieve.”

The smog is so bad , you can see it from space.

But this cloud of pollution

isn't actually coming from Delhi.

It's coming from here.

The states of Punjab and Haryana

are known as “India's Breadbasket.”

They're a key region for the country's agriculture.

Farmers here grow rice

and that requires large amounts of water.

In the 2000s, rice farming here took off,

and farmers in the area started using so much water,

that the region's groundwater started running low.

So, to save water, authorities passed a new act in 2009.

It bans rice planting before mid-June.

That means farmers can't plant rice

until right before the monsoon season,

when rains come to replenish the groundwater.

That pushes rice harvesting later into the year,

which means farmers have less time

to get their fields ready for their next crop.

So, to clear their fields more quickly,

more and more farmers have started

setting their crop stubble on fire.

Every year, all those stubble fires

form a massive cloud of smoke

during October and November.

And it heads straight for Delhi.

There are two reasons why smoke in this region

makes things worse in Delhi.

The first is geography.

The Himalayan mountains act like a kind of barrier,

directing the smoke towards Delhi.

The second is the weather.

During the winter, cold mountain air

rushes down from the Himalayas towards Delhi,

arriving beneath a layer of warm lowland air

that creates a kind of dome over the city.

The warm air keeps pollution trapped on the ground

with nowhere to go.

So when the stubble fire smoke arrives in Delhi,

it mixes with the urban pollution

forming a toxic smog that sits on top of the city.

Mix all that together and you have

the most hazardous air pollution of almost anywhere.

In November of 2019, India's Supreme Court

ruled that states in the North had to stop farmers

from burning their crop stubble.

But so far, the ruling

hasn't been enforced on the ground.

In the weeks after the ruling,

tens of thousands of crop fires

continued to burn in Punjab and Haryana.

Delhi doesn't have the ability

to stop crop burning in neighboring states.

Instead, when pollution spikes

in October and November,

city officials change the things they can control:

Sometimes they'll halt all construction in the city.

Or put restrictions on vehicle use.

Still, until India's ban on crop stubble burning

is actually enforced,

these spikes will be back every year.

Making the city's already dangerous pollution

even worse

and putting the lives of millions at risk.

" I've lived in Delhi for over 50 years. Where will we go ?"

" Our livelihood is here."

“Here we are taking baby steps,

but we are in a time period where

baby steps won't help anymore.”

“What we breathe should be fresh air.”