1. Chandni Chowk, Chawri Bazar, Sadar Bazar - the best one in whole Delhi.
2. Laxmi Nagar- Nirman Vihar Stretch
3. Lajpat Nagar Central Market ( only 7-8 shops) Dolma Aunty's Momos are good
4. North Campus, Bhelpuri wale uncle near Patel Chest, And a few chat shops near Malkaganj, and some more near Hudson Lane.
When it comes to street food and you want to have something heavy and yummy there's a place called kulcha junction at connaught place behind the Bangla sahib gurduwara they have the crunchiest kulchas and so hot the is gonna burn ur fingers with loads of makhan on it it's a must try place if you drooling already