THERE was no mushroom cloud. But the ripples caused by India's decision to block the Comprehensive Test Ban Treaty (CTBT) were perhaps as powerful and far reaching as the political impact of the nuclear device it exploded in 1974. And the reaction was immediate. The day after India formally blocked the treaty, the head of the US Arms Control and Disarmament Agency director, John Holum, told an American newspaper that India will have to "pay a price" for blocking this treaty.