depreciation

Yes, u/s. 32 of IT act................

yes, deprecation allowed as a deduction to business and professionals

Yes,if the below basic 2 conditions to follow
1.Ownership(includes Beneficial)
2.Used for business or profession.

Assessee should follow merchandise method(accrual) and maintaining assets under block wise.
Depreciation under IT Act is
a.Normal Depreciation(u/s 32)
b.Additional Depreciation
c.Investment Allowance(u/s 32AD)

Please refer Annexures for the above mentioned provision in IT Act,1961.

Sekhar what if the property in which business operates is not owned but is on.lease ,,can deprecation be claimed on it by the company or professional

Dear kashyap
As IT Act,Lessor only eligible to claim depreciation on leased asset based on some supreme court's judgement.

and what if residential property being used in the business or profession

As per section 38(2) of IT act.... depreciation allowed on proportionate basis.i.e, %of house property used for business/profession.