Selection process......

Eligibility
Article 84 of the Constitution sets the principle qualifications one must meet to be eligible to the office of the Prime Minister. A Prime Minister must be:

• a citizen of India
• should be a member of the Lok Sabha or Rajya Sabha
• of 25 years of age (in the case of a seat in the House of the People) or above 30 years of age (in the case of a seat in the Council of States)

A person shall not be eligible for election as Prime Minister if he holds any office of profit under the Government of India or the Government of any State or under any local or other authority subject to the control of any of the said Governments.