Can I pursue B.Sc in agriculture or B.Sc in environment science after completing my 12th with science stream & PCM as my subjects?

You may not be eligible for B.Sc agriculture as requirement for this in most of the universities is 10+2 with physics, chemistry, biology and mathematics. If you look into Dr Panjabrao Deshmukh Agricultural University, you need to study physics, chemistry, biology and mathematics and if you have not