Hey,
There are few really good colleges in India that offer B.Sc in Economics like St.Xavier's, Kolkata.DAV College, Amritsar.Ananda Chandra College.Christ University, Bangalore.Presidency Univerity, Kolkata.
Symbiosis School of Economics, Pune.MIT World University,Pune.Most of the colleges offer BA in Economics.
Here is the list of the colleges that offer B.Sc in Physics,Chemistry,Stats and Mathematics:
Pune-
Fergusson College,Modern College of Arts,Science and commerce,Savitri Bai Phule Pune University
Hyderabad-
Osmania University,Nizam College,University of Hyderabad ,Government City College
Jaipur-
Jaipur National University ,Mahatama Jyoti Rao Phule University,Maharaja College,Suresh Gyan Vihar University
Delhi-
Hindu College,Sri Venkateswara College,Ramjas College,Hansraj College.
Hope  this  helps.

Hello Renu,


Colleges in Pune are,

Fergusson College

M.E.S. Abasaheb Garware College

MIT World Peace University - MIT

Sinhgad College of Science - [SCOS] Ambegaon

Modern College of Arts Science and Commerce - [MCASC] Shivajinagar

Colleges in Jaipur are,

Lal Bahadur Shastri PG College

Jaipur National University - [JNU]

University of Technology - [UOT]

SS Jain Subodh PG College

Colleges in Hydrabad are,

St Francis College for Women

GITAM School of Science

St Ann's College for Women

A.V. College of Arts Science and Commerce - [AV College]

Colleges in Delhi are,

Ramjas College

Mangalayatan University - [MU]

Sri Venkateswara College

All the Best