Hi Mohit,

To be able to get admission in BSc honors, you should have the following eligibility criterion:-

• 10+2 should be completed from a reputed organization.
• 10+2 should be in science stream
• Maths/Biology, Physics, Chemistry, and English should be compulsory subjects in +2

Some institutes like Annamalai University gives lateral entry in 2nd year if you have cleared 1st year with 75%

Also, some institutes like IGNOU offers long distance courses for those who are unable to attend. 

hope this helps