Calcutta is a poor example for either of you to use, firstly because it's not capitalist and secondly because the modern situation there is a bit more complex than the western media portrays it. Calcutta is part of teh state of West Bengal, governed since 1977 by the Communist Party of India-Marxist. In practice, even the well-intentioned and honest Communist leader, Jyoti Basu (now in his 80s) has not been able to provide food, shelter and healthcare for everyone, hence his welcoming attitude towards Mother Teresa and company. He has, however, accomplished three major goals:
1) he managed to greatly reduce the inf;lux pof people into Calcutta by funnelling money into rural development
2) he made Calcutta have the most unionized workforce in India, with very powerful unions. there is no question about who rules the roost in calcutta. If workers want to renegotiate their wages, they have the right to surround and harass the bposs till he is forced to give them what they deserve.
3) West Bengal has not, in apite of its being cursed by nature and history, a famine since the last days of capitalism in the mid-40s. Under the British millions of people died, but Jyoti's communist regime has avoided a similar mass starvation.
In other words, to sum up, the slums of Calciutta are terrible, but they are much better than what they COULD have been, if the government had been unconcerned about the poor.
As for the reasons why people flood into Calcutta and live in slums, I dpon't think it's because Calcutta is a capitalist mecca overflowing with low-wage jobs. People come to Calcutta because,
1) it has a communist government which upholds teh rights of teh poor
2) it has a Christian care-giving program (Motehr Teresa)
3) it was a fairly peaceful nd democratic refuge for teh Bangladeshis during the east Pakistan war.
4) it has less floods, hurricanes etc. than Bangladesh.
5) it's a refuge from the horrible barbarism, caste prejudice and feudalistic poverty of nearby Bihar (one of the worst-off places on earth).
So in conclusion, Calcutta is a complex situation. Don't sue it as an example of capitalsim producing horrible conditions, because 1) it's not capitalist and 2) teh conditions are a lot better than they might be otherwise. The real problem with Calcutta is that the governments of idnia, historically social-democrat, had petty squabbles with the Communists and so cut off much of their aid. Also, businesses began leaving the state as teh workforce became more emancipated. Given the opportunity to be more left-wing, and to nationalize some of these businesses to keep them in-state, I'm sure that Jyoti Basu would have been able to do even better with Bengal.
(Final note- west Bengal continues to be the intellectual capital of India)