illegal construction on a government street .

You can give a complaint to the local civic body within the jurisdiction to initiate legal action against the encroacher, if the civic body is not taking any action on this then you can file a PIL before high court in this regard and seek direction to the concerned local civic body to take action to retrieve government land as per law.

Very well analysed, opined and advised by learned expert Mt. TKalaiselvan, I fully agree.

Besides aforesaid action(s) you may institute a suit for permanent and mandatory injunction against encroacher and civic authorites (after taking leave of jurisdictional civil court) under section 91 of the Code of Civil Procedure, 1908 through a local prudent lawyer, which reads as:

91. Public nuisances and other wrongful acts affecting the public

1 ,2[(1) In the case of a public nuisance or other wrongful act affecting, or likely to affect, the public, a suit for a declaration and injunction or for such other relief as may be appropriate in the circumstances of the case, may be instituted,

(a) by the Advocate-General, or

(b) with the leave of the Court, by two or more persons, even though no special damage has been caused to such persons by reason of such public nuisance or other wrongful act.]

(2) Nothing in this section shall be deemed to limit or otherwise affect any right of suit which may exist independently of its provisions.

can also complaint to the SDM for action u.s 133 CrPC