The bus, traveling overnight from Bangalore to Hyderabad, was passing another vehicle when it crashed into the roadside barrier in Mehabubnagar in Andhra Pradesh, police official Naveen Kumar Chand said. The diesel tank then caught fire, and flames engulfed the bus.
The victims included a baby, a couple celebrating their 23rd wedding anniversary and several software engineers returning home to Hyderabad from jobs in Bangalore, the transportation minister said.
Angry relatives gathered at both the Bangalore and Hyderabad offices of Jabbar Travels, forcing police to send officers to keep order. Police were also searching for the company's owners in Bangalore, the main city in the neighbouring southern state of Karnataka.
India has the highest annual road death toll in the world, according to the World Health Organization. More than 110,000 people are killed every year in road accidents across the country, according to police.
Most crashes are blamed on reckless driving, poorly maintained roads and aging vehicles.
The recent crash happened more than 1,200 kilometres from India's capital, New Delhi.
- AP