Government servant asa member of Co-Operative society

Yes. He can.  But he should inform his superiors about this in writing.

Out of context, I am commenting that the Government servant should not be a member of the political organisation, which rule is illegal,unjustified, ultravires and liable to be set aside.  But all the Courts of law validated this repugnant rule.  I really wonder that a communist leader (late Sh. Inderjeet Gupta) can become Home Minister, but a communist cannot become a LDC in Home Ministry.  What an irony?