Bombay is the financial capital of India. Nothing strange that Delhi is the political capital, because in a lot of big countries the political capital and the financial capital are different. Eg: Australia (Canberra/Melbourne), US (Washington/NewYork), China(Beijing/Shanghai).
It is because the financial activities cannot stand delays and other beurocratic burdens which is so much prevelant in Delhi in terms of traffic hold-ups whenever a VIP passes the way.
India is unthinkable without Bombay. Bombay is a huge activity of finances of all kinds. She contributes 35% of individual income taxes, 50% of the service taxes, and 44% of the corporate taxes in a year.
And all these funds are consumed by Delhi to build wider roads for their politicians. Delhi is like a parasite to India.
Bombay is the producer of wealth for the country. If a substantial portion of the wealth that Bombay generates comes back as investment to her, today we could have a Shanghai of India. But this is not to be because of our political class, who has vested interests.
She has also the most developed public transport system in India. Second is Calcutta.