The Supreme Court of India has asked candidates in elections to make public the source of their income along with that of their spouses and dependents.

A Supreme Court bench comprising Justices J Chelameswar and S Abdul Nazeer passed the order on Friday that the Indian government amended the relevant electoral rules to incorporate the provision on declaration of source of income of candidates and their spouses and dependents.

Voters have a fundamental right to know all relevant information about the candidates including their sources of income, said the Indian apex court giving its significant judgement on a public interest litigation filed by an NGO.

The bench made it clear that non-disclosure of the information by candidates would constitute a corrupt practice falling under heading undue influence as defined under the Representation of People Act and the election of the candidate could be quashed if elected.

It also said the candidates would also have to provide information regarding contracts with any government agency or public sector undertakings either by them or spouse and dependants.

The apex court said the experience of the first 50 years of the functioning of democracy in the country disclosed some undesirable trends that have crept into its working and it was necessary to deal with it on urgent basis to maintain purity of the electoral process.

It said undue accretion of assets of lawmakers was a "sure indicator" of the beginning of a failing democracy which, if left unattended, would lead to the destruction of democracy and pave the way for the "rule of mafia".

The bench said the government must set up a mechanism to "continuously" monitor assets and sources of income of legislators and their associates.

The bench pointed out that there were known cases of legislators or their associates availing huge amount of loans for alleged commercial purposes from public financial institutions, either directly or through corporates controlled by them. Such loans become non-performing assets.