Stalking concern

My aunt in Gurgaon was being stalked by a Tata car on gold course road, black SuV most likely harrier. The car followed her across the main road and U turn then slowed seeing Cops. She got scared though they went out of sight so entered a known society of her friends, leaving car and called helpline from there when she saw the same car taking a U turn in front of her and passing by on the main revenue road, and they may have seen and noted her car number. She has the vehicle number anyway to report and what next steps?