1. Reasonable Restrictions
Article 19(2) of Indian Constitution

2. The areas restricted
Reasonable limits or restrictions can be imposed on the exercise of freedom of speech and expression under Article 19(2) in the interests of : Security of the state, friendly relations with foreign countries, public order, decency and morality, contempt of court, defamation, incitement to an offence, and sovereignty and integrity of India.
Security of the state: restriction can be imposed on speech which tends to incite or encourage people to commit violent acts like murder or rebellion against the state. It was added through a constitution amendment in 1951.

3. more
Friendly relations with foreign countries: This was also brought in through the 1951 Amendment to avoid embarrassment to India through malicious propaganda. The restriction can be loosely interpreted to include any criticism of India’s foreign policy.
Public order: This restriction too was added in 1951 to overcome the situation arising out of the Supreme Court judgment in Romesh Thapar case, where it was held that ordinary breaches of public order was no ground for imposing restrictions.

4. more
Decency and morality: The restriction is imposed with a view to safeguard the society from depraved and corrupt actions or behaviour. An example in point is the banning of Lady Chatterley’s Lover using the Hicklin test for obscenity laid down by the court in England.
Contempt of court: The main reason behind this restriction is to preserve the authority of the courts in meting out justice. Today the courts are taking a very liberal view in accepting bona fide criticism in its working.
Defamation: The freedom of speech and expression does not entitle a citizen to defame another. Defamation is defined by Section 499 of IPC as exposing a man to hatred, ridicule or contempt.

5. And more
Incitement to an offence: This clause added in 1951 allows the state to impose restrictions in the interest of security of state where there is an incitement to murder or any other violent acts.
Sovereignty and integrity of India: This restriction was added by the 16th Amendment in 1963 so as to not permit anyone to challenge the integrity or sovereignty of India or preach cession of any part of the country