RTI stands for Right to Information. Right to Information is a part of fundamental rights under Article 19(1) of the Constitution. Article 19 (1) says that every citizen has freedom of speech and expression. As early as in 1976, the Supreme Court said in the case of Raj Narain vs State of UP, that people cannot speak or express themselves unless they know. Therefore, right to information is embedded in article 19. In the same case, Supreme Court further said that India is a democracy. People are the masters. Therefore, the masters have a right to know how the governments, meant to serve them, are functioning. Further, every citizen pays taxes. Even a beggar on the street pays tax (in the form of sales tax, excise duty etc) when he buys a piece of soap from the market. The citizens therefore, have a right to know how their money was being spent. These three principles were laid down by the Supreme Court while saying that RTI is a part of our fundamental rights.

If RTI is a fundamental right, then why do we need an Act to give us this right? 
This is because if you went to any Government Department and told the officer there, “RTI is my fundamental right, and that I am the master of this country. Therefore, please show me all your files”, he would not do that. In all probability, he would throw you out of his room. Therefore, we need a machinery or a process through which we can exercise this fundamental right. Right to Information Act 2005, which became effective on 13th October 2005, provides that machinery. Therefore, Right to Information Act does not give us any new right. It simply lays down the process on how to apply for information, where to apply, how much fees etc