THE issue of caste in politics has again leapt into the limelight with the appointment of a Dalit, or low caste woman, as chief minister of Uttar Pradesh. Mayawati, of the Bahujan Samaj Party (BSP), or downtrodden people's party, who was sworn into office yesterday, became independent India's first state chief minister from the 'untouchable' caste. She replaces Mulayam Singh Yadav, whose 18-month coalition government was dismissed after the BSP withdrew support following incessant caste and community rivalries. Political analysts say Mrs Mayawati's appointment signals the end in Indian politics of upper caste domination over the numerically superior, albeit economically and socially deprived, lower castes. In neighbouring Bihar state, for instance, the Janata Dal, a party of the lower castes, was recently voted to power. 'If the BSP can organise itself better, it has the numbers to emerge as India's major political force,' said an analyst. The BSP's legislators were in constant, often violent confrontation with Mr Yadav's supporters, most of whom are agriculturists from marginally higher caste or backward communities, as they are officially classified. The 40-year-old chief minister who has to prove her majority within 15 days in the 425-member state assembly, is now busy trying to form a coalition along caste and community lines. She is supported by the Hindu fundamentalist Bharatiya Janata Party, the single largest party in Uttar Pradesh, India's most populous state. And, although the Bharatiya Janata Party is a party of high caste Hindus, it is opposed to Mr Yadav's backward community supporters and wants them out of office. India's rigid caste system - a complex social order in which certain groups are elevated above others - originated thousands of years ago and divides society into four castes with thousands of sub-castes. The highest are the Brahmins and the lowest, mostly manual labourers, are the Sudras. In between are the Kshatriyas, or warriors, and the Vaishyas, or traders. Existing outside this rigid system are the Untouchables - outcasts generally associated with 'unclean' jobs like removing human waste and scavenging. It is from this huge number - estimated at around 50 per cent of the population - that the BSP, founded in the early 1980s, draws support. Kanshi Ram, the BSP's leader, has been organising lower castes into a political force, trying to turn its numerical strength into India's largest voting block. Caste has always been a key factor in political and economic dominance in India. While publicly eschewing the caste system as 'regressive', Indian politicians have always counted on votes along caste lines.