4. Employer's liability to deduct and pay tax on behalf of employees

(1) The tax payable under this Act by any person earning a salary or wage shall be deducted monthly in the prescribed manner by his employer from the salary or wage payable to such person before such salary or wage is paid to him and such employer shall, irrespective of whether such deduction has been made or not, when the salary or wage is paid to such person, be liable to pay tax on behalf of all such persons:

Provided that if the employer is an officer of the Central Government or a State Government, such employer shall discharge the said liability in such manner, as may be prescribed.

(2) When any person earning a salary or wage -

(a) is also covered by one or more entries other than entry 1 of the Schedule and the rate of tax in any such other entry is more than the rate of tax under entry 1 of the said Schedule,

(b) is simultaneously in employment of more than one employer,

and such person furnishes to his employer a certificate in the prescribed Form declaring that he has been registered under sub-section (2) of Section 8 and shall pay the tax himself, then the employer or employers of such person shall not deduct the tax from the salary or wage payable to such person and such employer or employers, as the case may be, shall not be liable to pay tax on behalf of such person :

Provided that such person may opt to have the amount of tax deducted by the employer or employers from his salary or wage and thereupon the amount so deducted shall stand adjusted towards the tax payable by such person for the year.