As I said, Kolkata is far older than B'lore and very close to Bangladesh and also there's no big city nearby. So obviously there are a lot of immigrants, the population is very high (16-17M) and hence the chaos. Regarding the poverty, the low cost of living balances it out. I'd say if someone earns <10k per month, he/she would be considered poor in B'lore where as in Kolkata, you can lead a much better life. The southern and eastern Kolkata areas are pretty developed. And the roads are way better than B'lore. Most of your bong friends don't want to go back to Kolkata probably because they are SW Engrs and options are pretty limited there. As someone said, you will never have basic problems like food and water. Even I had thought Bangalore is probably the best city to live in before moving here permanently. But now I can see many places which are within 7-10km of the heart of the b'lore and still do not get water supply or good roads. Kolkata has much higher traffic than B'lore but because of the narrow roads and never ending fly overs/underpasses/diggings, the traffic seems worst in B'lore. The main -ve points in Kolkata are the political problems and lack of law/discipline.
Oh and FYI, I am from Bengal and my home is 55km from Kolkata. Also, I did my graduation in Kolkata and I don't agree to you that I haven't seen Kolkata mate
gREen, chennai has changed a lot my friend. After immense industrial growth in the past few years, the cost of living is almost touching B'lore these days. The worse part is, even if you go 60km from main city, cost of living won't come down much.