Now, Punjab withdraws general consent to CBI
Punjab has joined the Opposition-ruled states that have withdrawn general consent for an investigation by the Central Bureau of Investigation (CBI).
A notification, issued on November 8, makes it necessary for the Central agency to get permission from the Punjab Government to conduct investigations in the state.

Eight other states such as Chhattisgarh, Jharkhand, Rajasthan, West Bengal, Maharashtra and Kerala had withdrawn the general consent earlier, alleging that the BJP-led government at the Centre was misusing the agency to harass its political opponents.

Punjab had earlier withdrawn consent to the CBI to investigate sacrilege cases. The matter was caught in legal tangles and is presently being heard in the Punjab and Haryana High Court. 

What is CBI:-
Central Bureau of Investigation (CBI) is the premier investigating police agency in India.
It functions under the superintendence of the Deptt. of Personnel, Ministry of Personnel, Pension & Public Grievances, Government of India - which falls under the prime minister’s office.
However for investigations of offences under the Prevention of Corruption Act, its superintendence vests with the Central Vigilance Commission.
It is also the nodal police agency in India which coordinates investigation on behalf of Interpol Member countries.

What is general consent:-

CBI is governed by the Delhi Special Police Establishment Act that makes consent of a state government mandatory for conducting investigation in that state.
There are two kinds of consent:
Case-specific and general. Given that the CBI has jurisdiction only over central government departments and employees, it can investigate a case involving state government employees or a violent crime in a given state only after that state government gives its consent.
 

Can States bar the Central Bureau of Investigation (CBI) from functioning in their territory:-

The CBI is a national agency with police powers. Its primary jurisdiction is confined to Delhi and Union Territories.
As policing (detecting crime and maintaining law and order) is a State subject, the law allows the agency to function outside only with the consent of the States.
Section 6 of Delhi Special Police Establishment Act the Act says, “Nothing contained in Section 5 (which deals with jurisdiction of CBI) shall be deemed to enable any member of the Delhi Special Police Establishment to exercise powers and jurisdiction in any area in a State, not being a Union Territory or Railway, area, without the consent of the Government of that State.”
 

Has it happened before? And why:-

There are several instances of State governments withdrawing their consent. There was even an instance in Sikkim, when the State withdrew its consent after the CBI registered a case against former Chief Minister Nar Bahadur Bhandari, and before it could file a charge sheet.
The most common reason for withdrawal of consent is a strain in Centre-State relations, and the oft-repeated allegation that the agency is being misused against Opposition parties.
The decision by Andhra Pradesh and West Bengal has come amid concerns being voiced by Opposition parties that Central agencies such as the CBI, Enforcement Directorate and Income Tax Department are being used against them.

Under what law is it done:-

The CBI draws its power from the Delhi Special Police Establishment (DSPE) Act. The Home Ministry, through a resolution, set up the agency in April 1963.
Under Section 5 of the Act, the Central government can extend its powers and jurisdiction to the States, for investigation of specified offences.
However, this power is restricted by Section 6, which says its powers and jurisdiction cannot be extended to any State without the consent of the government of that State.

What is the impact of States taking back their consent:-

The withdrawal of general consent restricts the CBI from instituting new cases in the State concerned.
Supreme Court in Kazi Lhendup Dorji (1994), the withdrawal of consent applies prospectively and therefore, existing cases will be allowed to reach their logical conclusion.
The CBI can also seek or get specific consent in individual cases from the State government.

How has the consent issue played out:-

In most cases, States have given consent for a CBI probe against only Central government employees. The agency can also investigate a Member of Parliament.
Apart from Mizoram, West Bengal and Andhra Pradesh, the agency has consent in one form or the other for carrying out investigations across the country.

What happens to cases in which there is a demand for a CBI probe:-

The Supreme Court has made it clear that when it or a High Court directs that a particular investigation be handed over to the CBI, there is no need for any consent under the DSPE Act.
A landmark judgment in this regard was the 2010 Supreme Court decision by which the killing of 11 Trinamool Congress workers in West Bengal in 2001 was handed over to the CBI.