HUGE, MIXED, democratic India lives with a level of civic disorder that would sink many other states. But the explosion that took place Sunday, when Hindu extremists destroyed a four-century-old Muslim mosque, has stirred fears that the country is entering its gravest crisis since independence. There was a long run-up to the explosion at Ayodhya, which provoked a reaction there and elsewhere in India and beyond that took hundreds, perhaps thousands of lives. In its wake a country constitutionally devoted to secularism now comes under perhaps unbearable religious and communal strains.

It is tempting to attribute these troubles either to traditional, self-driven cultural "forces" or to the sort of ethnic passions that have become global common coin in the few years since the Cold War ended. But this is to misread the responsibility of the political leadership for this particular deadly sequence. The national government of Prime Minister P. V. Narasimha Rao must accept its share of blame for allowing this dispute to flower. A much larger share must be put on the right-wing Bharatiya Janata Party, which saw to the destruction of the Ayodhya mosque and to the immediate and provocative construction of a makeshift Hindu temple in its place. In the BJP's shameless and cynical exploitation of religious tensions for political gain lies the chief source of India's latest turn.

India's 120 million Muslims make up an eighth of the population. They have yet to find a full economic or political place in the country, but Hindu militants have still succeeded in mobilizing much popular resentment against them. Since last Sunday, Prime Minister Rao has moved vigorously to take the immediate situation in hand, but the larger task is for India's democracy to find in itself a capacity to widen social opportunity and enforce the rule of law. Economic growth would ease the tension, but tolerance must be pursued in many ways. Secularism was the basis on which mostly Hindu India set out at independence to build a democracy. The effort has never been more essential.