Sukanta,
there is no minimum basic for EPF deduction but now days the EPFO is pressuring the establishment under EPF to deducted PF at minimum wages but in the judgement of the Punjab & Haryana High Court the Bench ruled that minimum wages in "Minimum wages Act" never been defined as basic wages for the "EPF act".
So you can deduct on any amount as you want, but please remember that in salary split PF must be deducted on basic + da (it can be 40% or 60% of the gross salary)
For minimum wages update check out
Minimum Wages in West Bengal
EC = Enrollment Certificate RC = Registration Certificate
rahulplatys ESI is applicable on IT organisation such as you stated, but keep in mind that applicability is only on production i.e. some output must be there for ESI to cover the establishment.
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