Karachi, Pakistan, a mega city of more than 20 million people.

Ambulance driver, Mohamed Safdar, has been navigating its streets for the past 16 years.

Whenever I'm going out and I'm saving people, there's this drive I get when I'm on a job

that I will do this, I can do this. Most people flee danger, but Safda's work means he heads

towards it. In our religion, in Islam, what we are taught is when you save one person's life, you're saving all of humanity.

And that is kind of at the core of my belief.

And that is what drives us.

I'm Samira Shackle.

And for the BBC World Service,

I'm with Karachi's ambulance drivers.

I've got family in Karachi,

and I've been reporting on the city for almost 10 years.

In that time, I've seen it racked by conflict,

ranging from gang wars to political violence and terrorism,

which has gone on for decades.

There are many sectarian or ethnic divides in a country, but whenever we're going to

save someone, we don't ask what

kind of ethnicity there are. We think about humanity. We think about just saving a human being.

Throughout all this turbulence, the city's ambulance drivers have put themselves in grave danger

for little financial reward. But the last few years have brought a

drastic change to Sautra's work. Ever since 2014, when the army and police began a harsh

crackdown against organised crime and terror groups, things have been progressively calmer,

...