If you are late for work in Mumbai and reach the station just as the train is leaving the platform, don't despair. You can run up to the packed compartments and find many hands unfolding like petals to pull you on board. And while you will probably have to hang on to the door frame with your fingertips, you are still grateful for the empathy of your fellow passengers, already packed tighter than cattle, their shirts drenched with sweat in the badly ventilated compartment. They know that your boss might yell at you or cut your pay if you miss this train.

Bombay as a confident, welcoming city that takes in a million new people a year, that those who want to harm the country pick Bombay. Other Indian cities, such as Delhi and Varanasi, have also been bombed recently, but Bombay's significance as the financial capital of the country means that it's the best target for terrorists who're unhappy with India's progress.

I am an exile; citizen of the country of longing.

While I was writing my book, I got a top police official in Bombay an invitation to study terrorism at the Rand Institute in Washington DC. This would have helped the city enormously, as he was the detective who cracked the '93 blasts case. But the commissioner declined to let his subordinate take up the offer from Rand, because of his fear that it was CIA-affiliated. That culture of suspicion needs to change; India needs to learn how other democracies fight terror.

It was when I realised I had a new nationality: I was in exile. I am an adulterous resident: when I am in one city, I am dreaming of the other. I am an exile; citizen of the country of longing.

There have always been elements in the Pakistani state that have been hostile to India; which is not to say that the Pakistani government as a whole is responsible for bombing Indian cities. But I think there are entities in the Pakistani security services that operate more or less autonomously. Their role certainly needs looking into.

Commuter trains are the easiest target for terrorists, as we have seen in Madrid, London, and now Bombay. But it is difficult for a Westerner to comprehend the kind of overcrowding in a Bombay local train; they ferry six million passengers a day. A bomb that goes off in one of those compartments will have maximum impact.