TDS stands for tax deducted at source.

 For quick and efficient collection of taxes, the Income-tax Law has incorporated a system of deduction of tax at the point of generation of income. This system is called as “Tax Deducted at Source”, commonly known as TDS. Under this system tax is deducted at the origin of the income. Tax is deducted by the payer and is remitted to the Government by the payer on behalf of the payee. 

The provisions of deduction of tax at source are applicable to several payments such as salary, interest, commission, brokerage, professional fees, royalty, contract payments, etc. In respect of payments to which the TDS provisions apply, the payer has to deduct tax at source on the payments made by him and he has to deposit the tax deducted by him to the credit of the Government.

As per the Income Tax Act, any company or person making a payment is required to deduct tax at source if the payment exceeds certain threshold limits. TDS has to be deducted at the rates prescribed by the tax department.

The company or person that makes the payment after deducting TDS is called a deductor and the company or person receiving the payment is called the deductee. It is the deductor’s responsibility to deduct TDS before making the payment and deposit the same with the government. TDS is deducted irrespective of the mode of payment–cash, cheque or credit–and is linked to the PAN of the deductor and deductee.

Consequences for not deducted tax at source.

A deductor would face the following consequences if he fails to deduct TDS or after deducting the same fails to deposit 
it to the credit of Central Government’s account:-
a)  Disallowance of expenditure
 
As per section 40(a)(i) of the Income-tax Act, any sum (other than salary) payable outside India or to a non-resident, which is chargeable to tax in India in the hands of the recipient, shall not be allowed to be deducted if it is paid without deduction of tax at source or if tax is deducted but is not deposited with the Central Government till the due date of filing of return.
However, if tax is deducted or deposited in subsequent year, as the case may be, the expenditure shall be allowed as deduction in that year.
Similarly, as per section 40(a)(ia), any sum payable to a resident, which is subject to deduction of tax at source, would attract 30% disallowance if it is paid without deduction of tax at source or if tax is deducted but is not deposited with the Central Government till the due date of filing of return.
However, where in respect of any such sum, tax is deducted or deposited in subsequent year, as the case may be, the expenditure so disallowed shall be allowed as deduction in that year.

As per Section 58(1A) (as amended with effect from the assessment year 2018-19), the provisions of section 40(a)(ia) and 40(a)(iia) shall also apply in computing the income chargeable under the head “Income from other sources”.

b)  Levy of interest

As per section 201 of the Income-tax Act, if a deductor fails to deduct tax at source or after the deducting the same fails to deposit it to the Government’s account then he shall be deemed to be an assessee-in-default and liable to pay simple interest as follows:-
(i) at one per cent for every month or part of a month on the amount of such tax from the date on which such tax was deductible to the date on which such tax is deducted; and
(ii) at one and one-half per cent for every month or part of a month on the amount of such tax from the date on which such tax was deducted to the date on which such tax is actually paid.​
 
c)  Levy of Penalty
Penalty of an amount equal to tax not deducted or paid could be imposed under section 271C​.