Hey,
Maths Honours is a three year program.
Here is the list of the some of the colleges offering B.Sc in Mathematics:
Christ University,Bangalore
Ferguson College,Pune
Hansraj College,New Delhi
Jamia Humdard,New Delhi
Banaras Hindu University
Sri Venkateswara College,New Delhi
Elphinstone College,Mumbai
The basic eligibility criteria to pursue B.Sc in Mathematics is to have passed 10+2 with science stream with atleast 50%marks in Mathematics or in aggregate.
Mathematics Major is split into two branches:Bachelor of Arts and Bachelor of Science.
So you may even go for BA in Mathematics.
Here is the list of the some of the colleges offering BA in Mathematics:
Dyal Singh College,New Delhi 
Hindu College,New Delhi 
Deshbandhu College,New Delhi 
St.Stephens College,New Delhi 
Aatma Ram Sanatan Dharma College,New Delhi 
The basic eligibility to pursue Bachelor's of Arts in Mathematics is having passed 10+2 from Science or Commerce stream with Mathematics as one of the subjects studied in Intermediate level

Hey.

Here is a list of a few top colleges for pursuing Mathematics Hons degree in India.

St. Stephen's College, New Delhi

Hansraj College, Delhi 

Hindu College, Delhi

Miranda House College, Delhi.

Christ University, Bangalore

Maulana Azad College, Kolkata

Kirori Mal College, Delhi.

Mount Carmel College, Bangalore 

Ramjas College, Delhi.

Jai Hind College, Mumbai

Sri Venkateshwara College, Delhi.

Best of luck