i have a 15 hours of stay at bejjing airport while going to russia do i need a transit visa ?

hi please help me with my question i am very depressed for it....
i have to visit russia for a study purpose from india,
and i have got flight from india to russia via china (bejing airport) and my stop over is around 15.20 hours
do i need to get a transit G also
since i have got my return ticket from india to russia .
and both way i have a stopover in china for 15 hours ?