Need of service tax registration by jobworker

There is exemption provided under Notification No.25/2012-ST dated 20-06-2012;

Carrying out an intermediate production process as job work in relation to –
a	Agriculture[1], printing or textile processing;
b	Cut and polished diamonds and gemstones; or plain and studded jewellery of gold and other precious metals, falling under Chapter 71 of the Central Excise Tariff Act,1985 (5 of 1986);
c	Any goods8 on which appropriate duty[2] is payable by the principal manufacturer[3]; or
d	Processes of electroplating, zinc plating, anodizing, heat treatment, powder coating, painting including spray painting or auto black, during the course of manufacture of parts of cycles or sewing machines upto an aggregate value of taxable service¹⁵ of the specified processes of one hundred and fifty lakh rupees in a financial year subject to the condition that such aggregate value had not exceeded one hundred and fifty lakh rupees during the preceding financial year;

[1] 65B(3) “agriculture” means the cultivation of plants and rearing of all life-forms of animals, except the rearing of horses, for food, fibre, fuel, raw material or other similar products;

[2] 2(b) “appropriate duty” means duty payable on manufacture or production under a Central Act or a State Act, but shall not include ‘Nil’ rate of duty or duty wholly exempt;

[3] 2(z) “principal manufacturer” means any person who gets goods manufactured or processed on his account from another person;

Hence, if you are falling under the said exemption, then no service tax can be levied.