Dear Sudipta,
There is no specific guideline in this regard. In PF Act the definition of Basic is very specific. I have come across with some PF inspectors at the time of inspecting Organizations who have suggested to maintain 50% of gross salary as Basic up to 30,000/- monthly gross. Beyond that it may be tapper off i.e at 40,000/- monthly gross basic may be 18000/- (say) if the Organization is ready to pay voluntarily.
Thanks & Regds.,
S K Bandyopadhyay( Howrah, West Bengal)
USD HR Solutions
+9198310 81531