By Abhishek Prabhat BBC News, Delhi

Protestors argue that quotas will lead to lower standards

A protester also tried to set fire to himself at the rally in Delhi, according to reports.

Indian Prime Minister Manmohan Singh's pledge on Friday to increase places in higher education institutions failed to quell the protests.

A two-week strike continues to affect a number of state hospitals.

As the protesting doctors and medical students gathered in Delhi's Ramlila grounds, a man in the crowd tried to set fire to himself.

The protestors and policemen deployed at the venue doused the fire. The man, who is yet to be identified, was taken to hospital but is said to be out of danger.

'Peaceful' protest

The organisers of Saturday's protest, Youth for Equality, condemned the incident.

The new quotas would affect medical training institutions

The group said it plans to fight against the government's affirmative action plan in a peaceful way and such incidents would only hurt their campaign.

Hundreds of traders, teachers and other professionals took part in Saturday's public rally to protest against government plans to reserve half of state-funded professional college places for lower caste students from next year.

The protestors argue that the government plan would mean fewer places for upper caste students, and lower standards.

Prime minister Manmohan Singh promised on Friday to expand higher education in order to compensate for the introduction of quotas.

But the assurance failed to convince the protestors to call off their rally or their two-week strike at a number of state hospitals.

Thousands of doctors and medical students also marched in the eastern Indian city of Calcutta.

Poets, writers, artists and educationists also participated in the march.