B. R. Ambedkar was a Dalit (Untouchable) rights activist, who in the 1930s was convinced that Hinduism was not the right religion for Dalits and it was one of the main reasons Dalits were put in deplorable conditions. In 1935 he met with Christian, Muslim (Ambedkar would later speak out against Islamic ideologies in India), Sikh and Buddhist religious leaders, and he was swayed to become a Buddhist. When Ambedkar publically converted to Buddhism it lead to a mass conversion of Dalits to Buddhism. In fact a lot Buddhists in India have ancestors who were once Dalits.
But let's say that Ambedkar doesn't convert to Buddhism. How different would India be had Ambedkar converted to Islam, Christianity or Sikhism?