Abdul Rahman (45) suffered a heart attack and started sweating profusely while carrying 110 passengers from Sultan Battery to Pandalur, police said.
The Kerala State Transport Coporation bus then twice veered off course, but Rahman managed to take it to the side of the road and stopped after hitting a wall near Neelakottai. He then collapsed on the steering wheel and died, they said.
Police said the road has lots of curves and it was only the timely action of the driver that had prevented the bus from falling into a deep gorge.