Sandhya Rani, a 25-year-old receptionist, was on her way home when she was attacked at about 18:00 local time (12:30 GMT) on Thursday, police told the BBC.
People rushed to help Ms Rani but she died on her way to hospital.
The accused, Karthik Vanga, 28, is a former colleague.
He used to work in the same company as Ms Rani until a few months ago, police told the BBC.
When he approached her on Thursday, the two were seen arguing before the man pulled out a can of kerosene, poured the fuel on her and set her alight, police alleged.