Distance

Dear Pranab,
Yes, you may pursue Ph.D through distance in environmental science. For the list of the universities, you may refer the link below:
http://www.minglebox.com/science/courses/environmental-science/pg-phd-environmental-science

It is recommended that you may consider IIIT Bangalore PG Diploma in Data Analytic. If you want to do shorter course you may consider Manipal Global program on Business Analytic.

Yes ! Suma distance education is good option for people who cannot afford time to visit colleges. Some colleges provide placement support to their Distance Students too, You can also apply for government jobs based on your distance degree unless specified otherwise.SMU and Lovely Professional university are very good option for people seeking true value of their distance degree. As they provide placement support.

I would suggest you to complete your B.Sc as you have just 1 year ahead. After it you can take admission in B.Tech at various colleges like IIT, NIT, Lovely Professional University, VIT etc. As a lateral entry (direct admission in second year of b.tech course).
But if you are starting your second year now. I would advice to leave right away you would save 1 year of your life.
You may be eligible for a good scholarship too.

Dear shubham jain. apply to the symbiosis for correspondence course. later they will give complete details of the course. if it is possible why can't you prefer the course some best institute for fulltime. it will give best result for you.