But one man has devoted his life to making a difference.
Omkar Nath calls himself 'The Medicine Baba' and he collects the unused drugs people would otherwise throw away to give them to the poor.
South Asia Correspondent Michael Edwards has this reports from New Delhi.
Presenter: Michael Edwards, South Asia correspondent
Speaker: Omkar Nath, 'Medicine Baba'
(Omkar Nath calling out)
MICHAEL EDWARDS: During the summer New Delhi is a tough place to live.
It's hot and often muggy. The heat is compounded by heavy traffic and the fact that more than 20 million people are crammed into an area roughly the size of the metropolitan Sydney.
But it doesn't stop Omkar Nath pounding the pavements, calling on people to give him the medicines they don't need.
(Omkar Nath calling out: 'Please donate unused medicines. The ones you no longer need.')
MICHAEL EDWARDS: He calls himself 'The Medicine Baba' and the retired 75-year-old is hard to miss in his distinctive orange uniform which has his mobile number proudly displayed on it.
OMKAR NATH (translation): I want to bring change in society. I want to tell people that the medicines you throw away can be used to save other people's lives.
MICHAEL EDWARDS: His quest began after he witnessed a bridge collapse.
He saw dozens of people die. Many others were badly injured and he was shocked when he saw that the hospital they were taken to lacked enough drugs to treat them.
Such accidents are sadly common in India. They barely make the news, if at all.
It was a shocking experience for Omkar Nath.
OMKAR NATH (translation): The tragic thing was that I overhead the doctor say he did not have enough medicines. He was asking the family to arrange for medicines so he could treat them because he was out of stock.
MICHAEL EDWARDS: As the 'Medicine Baba', Omkar Nath walks the streets tirelessly for up to eight hours a day - not an easy thing to do given he has a limp and that the day we caught up with him, it was over 45 degrees.
He selects different parts of New Delhi and uses a roster to determine his movements.
He tells me his best clients are middle-class Indians - sometimes the richer people, he says, are not so generous.
But he says that when he started it was difficult to earn people's trust.
OMKAR NATH (translation): People thought that I was collecting the medicines to make money for myself. But after a while people realised I was doing this to help people.
But I have to admit that in the beginning even my wife thought I had turned to begging and refused to feed me unless I stopped it.
MICHAEL EDWARDS: From common cold remedies to expensive cancer treatments, the Medicine Baba only accepts items that are still within their use-by dates.
He's also started collecting walking frames and complicated equipment such as dialysis machines.
Mostly he gives the items to clinics and hospitals run by charities. These places are grateful for whatever help they receive.
It's estimated that more than half of India's 1.2 billion people are too poor to even afford everyday medicines. People die here every year from curable diseases such as the measles, pneumonia and hepatitis.
OMKAR NATH (translation): I get a lot of generosity from people, a lot of support, and I have been able to spread some awareness in society. Wherever I go now, people talk to me with a lot of respect and encouragement.
MICHAEL EDWARDS: It's hard work but the Medicine Baba says it's just his small way of making a difference.