Dear sir,

In the first model, citizenship is granted to all those who are born within the territory of the country, regardless of the nationality of the parents. ... As per Article 5 of the Constitution, a person with domicile in India is an Indian citizen, if : he is born in the territory of India, 

Citizenship by birth and descent

Countries all over the world follow two concepts of citizenship :

1. 
   'jus soli' (right of soil) or birthright citizenship
2. 
   'jus sanguinis'

   
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   (right of blood) or citizenship by descent.

In the first model, citizenship is granted to all those who are born within the territory of the country, regardless of the nationality of the parents.

In the second model, citizenship is granted to one based on the nationality of any of or both the parents, regardless of the place of birth.

India has been following a combination of both these models in its citizenship laws.

1. he is born in the territory of India, or
2. either of his parents was born in the territory of India.

So, domicile coupled with birth or descent are the main factors for citizenship.

It will be interesting to note that during the framing of the Constitution, some members argued for including religion as a factor for grant of citizenship. But this proposal was rejected by the Constituent Assembly, which envisioned India as a secular republic.

The Constitution also had provisions for granting citizenship to those migrated from Pakistan, based on fulfilling certain conditions (Article 6).

The Constitution also stated that a law made by Parliament on citizenship will have overriding effect on the provisions of Constitution (Article 11). The Citizenship Act passed by the Parliament in 1955 is that law. Various changes made to this law have considerably diluted the principle of jus soli for Indian citizenship.

Modes of acquiring Indian Citizenship

There are four modes of acquiring citizenship under the Citizenship Act 1955 :

1. Citizenship by birth
2. Citizenship by descent
3. Citizenship by registration.
4. Citizenship by naturalization.

Citizenship by birth (sec 3)

Section 3 of the Citizenship Act deals with Citizenship by birth.

When the law was first made in 1955, this Section stated that all those who are born in India on or after January 1, 1950 will be an Indian citizen.

This was amended in 1986, and birthright citizenship was limited to those who were born in India between January 1, 1950 and January 1, 1987.

An added condition that one of the parents must be an Indian citizen was introduced for granting citizenship to those who were born in India after January 1, 1987. It also changed the definition of 'Indian origin' by excluding from its purview those people whose grand-parents, but not parents, were born in India.

The condition for birthright citizenship was further tightened after 2003 amendment, which stated that those who were born after December 3, 2004 will be eligible for Indian citizenship only if one of the parents is an Indian citizen and the other is not an illegal migrant.

Any person born in India on or after 26 January 1950, but prior to the commencement of the 1986 Act on 1 July 1987, is a citizen of India by birth.

It depends on status of the parents first then only we can form opinion about status of child citizenship

1. Yes the person will be citizen of India by birth irrespective of parents being legal citizen or illegal immigrants.

2. Land documents of 1957 itself shows that father was Indian citizen when that person was born. 

A person born in India on or after 26th January 1950 but before 1st July, 1987 is citizen of India by birth irrespective of the nationality of his parents. considered citizen of India by birth if either of his parents is a citizen of India at the time of his birth.

Person born in India between 1950 to 1987 are Indian citizen.

You may go through the list of documents which are recognized as legal documents that can be produced to prove the citizenship. 

If this document appears in the list of documents then you can proceed. 

He acquires the Indian citizenship by birth alone irrespective of his land records and status of citizenship of his parents.

His parents were Indians then only he will be an Indian citizen.