Clad in simple cotton kurta pyjamas and turbaned against the punishing sunshine, Mr Singh stopped first to offer flowers at the shrine where Mahatma Gandhi was cremated. 'I will return to garland the first youth from the backward classes who gets a government job,' he said, 'or they will bring my mortal remains back to Delhi.'
Few within his Janata Dal party were sorry to see him go. A rough free-for-all is now expected to break out over who replaces Mr Singh as the party's parliamentary leader. At times, Mr Singh's philosophical airiness was at odds with socialists, Muslim leaders and brawling regional strongmen who lead the Janata Dal party. Despite his crusade for the underprivileged masses who make up over 75 per cent of Indian's 870 million people, Mr Singh himself never tasted prejudice: he was born into a landed, princely family.
Mr Singh blamed the Congress government for failing to comply with a Supreme Court ruling allotting 49 per cent of all central government jobs to those poor and backward Indians at the bottom of the Hindu hierarchy. Lowest down are the various tribes and 'untouchable' castes usually employed as sweepers, washermen, scavengers and labourers who comprise more than 200 million people. They hold a minuscule number of government positions. On the top end of the scale, Brahmins and other upper castes, who make up less than 18 per cent of the population, are said to control more than 99 per cent of northern India's top jobs in government, trade and industry.
Caste is almost as explosive an issue in Indian politics as religion. Mr Singh's revolutionary social experiment was partly to blame for his downfall. He lasted as prime minister for only 11 months, starting in December 1989. When he tried to enforce affirmative action for the lower castes, at least 80 Brahmin students around the country protested by burning themselves alive. The newspapers, most of which are owned and written by upper-caste Indians, also turned against Mr Singh, and waves of often violent strikes and protests battered his government.
As Mr Singh, a quizzical-looking man with glasses and a pencil moustache, vanished off down the heat-shimmering road leading out of New Delhi, few politicians were willing to place bets on when - or if - he would return. His goal is to follow Gandhi's footsteps, going into the villages and urging the people there to fight the discriminations of caste. 'The Janata Dal is not a party but a movement,' said Mr Singh. 'After suffering centuries of insult, it is time for the downtrodden to have a share in the power structure.'
This message of social upheaval is a potent one. Both the ruling Congress party and the leading right-wing Hindu nationalist Bharatiya Janata Party accuse Mr Singh of playing dangerous politics, though they are as guilty in this regard as him. Either Mr Singh succeeds in rallying the oppressed lower castes, or the farther he travels from Delhi the more his supporters will drift away, leaving him, as one newspaper put it, to wander India like a fakir - a holy beggar.