Miranda House, Delhi

Hindu College, Delhi

St Stephen's College, Delhi

Kirori Mal College, Delhi

Loyola College, Chennai

Madras Christian College, Chennai

Hansraj College, Delhi

Department of Sciences, Christ University, Bengaluru

Stella Maris College, Chennai

Women's Christian College, Chennai

Deen Dayal Upadhyaya College, New Delhi

Atma Ram Sanatan Dharma College, New Delhi

Mount Carmel College, Bengaluru

Gargi College, New Delhi

St Joseph's College, Bengaluru

Mithibai College, Mumbai

St Xavier's College, Mumbai

Goswami Ganesh Dutta Sanatan Dharma College, Chandigarh

Maharaja Agrasen College, New Delhi

Acharya Narendra Dev College, New Delhi

Hello Aspirant. 

Top 20 science colleges in India are: -

1. Miranda House, Delhi

2. Hindu College, Delhi

3. St Stephen's College, Delhi

4-Kirori Mal College, Delhi

5-Loyola College, Chennai

Madras Christian College, Chennai

7-Hansraj College, Delhi

8-Department of Sciences, Christ University, Bengaluru

9-Stella Maris College, Chennai

10- Women's Christian College, Chennai

11-Deen Dayal Upadhyaya College, New Delhi

12-Atma Ram Sanatan Dharma College, New Delhi

13-Mount Carmel College, Bengaluru

14-Gargi College, New Delhi

15-St Joseph's College, Bengaluru

16-Mithibai College, Mumbai

17- St Xavier's College, Mumbai

18-Goswami Ganesh Dutta Sanatan Dharma College, Chandigarh

19-Maharaja Agrasen College, New Delhi

20-Acharya Narendra Dev College, New DDelhi. 

I hope my answer will help you, all the best.