Lack of definition of minority and backward in coi

What you stated is true, and I think there is Nehru report as well as Sapru report in this regards. But for what kind of people are you refering as backward class of people, as such class of people can not exist in a vacum.

What is the context in which the query has been posted?

Minority communities in India includes Muslims, Sikhs, Christians, Buddhists, Parsis and Jains. The scholarship is awarded to the students by India Government through State Government/UTs. ..

Linguistic Minorities, according to Indian Constitution should have a Special Officer appointed.

The Constitution of India uses the word 'minority' or its plural form in some Articles viz Article 20 to 30 and 350 A to 350 B, but does not define the word 'minority'.

 As regards religious minorities at the national level, all those who profess a religion other than Hinduism are considered minorities.

Backward:

It is defined as a stratum of people who share similar socio-economic status or position. It is relatively open as compared to other forms of stratification like caste. A class is considered to be backward if its members are economically and educationally less privileged compared to other classes in that society.

The backward classes in India are socially, economically and educationally most backward section of Indian society.

A class is considered to be backward if its members are economically and educationally less privileged compared to other classes in that society.

The ‘backward class’ does not constitute one single whole but a multitude of social groups with varying positions and socio-economic standing in the social hierarchy of Indian society.

The backward classes suffer from disadvantages and disabilities which are age- old. Low status, poverty and illiteracy are social problems which they have inherited due to their ascribed status of being born in a low caste or tribe. The Indian Constitution is silent on the definition of the backward classes.

Minority as per constitution:

The Constitution of India uses the word ‘minority’ or its plural form in some Articles viz Article 20 to 30 and 350 A to 350 B, but does not define the word ‘minority’. The Motilal Nehru Report (1928) showed a prominent desire to afford protection to minorities, but did not define the expression. In pursuance of the Constitutional provisions, the government is committed to the well being of the minorities- whether linguistic or religious.