The Supreme Court on Monday restrained authorities from cutting anymore trees in Mumbai's Aarey to set up a Metro car shed.

A special bench comprising justices Arun Mishra and Ashok Bhushan said it will have to examine the entire thing and posted the matter for hearing on October 21 before its forest bench.

"Don't cut anything now," the bench said.

The felling of trees is being opposed by green activists and local residents.

The apex court directed that if anybody is still under arrest for protesting the cutting of trees, they should be released forthwith on furnishing of personal bonds.

During the hearing the Maharashtra Government told the bench that all those arrested for protesting against cutting of trees in Aarey have been released.

Solicitor General Tushar Mehta, appearing for the Maharashtra Government, submitted that he was not aware of all records and assured the bench that nothing will be cut in Aarey till the case is decided.

The PIL petitioners told the bench that Aarey forest was deemed as an "unclassified forest" by the state government and felling of of trees was illegal.

However, after perusing the notification issued by the Maharashtra government, the bench said, Aarey area is a no development zone and not a eco-sensitive zone as claimed by the petitioner.

The apex court decided on Sunday to register as PIL a letter addressed to Chief Justice of India Ranjan Gogoi by law student Rishav Ranjan seeking a stay on cutting of trees.

A notice was posted on the Supreme Court website about holding the urgent hearing by constituting a special bench.

The Bombay High Court had on October 4 refused to declare Aarey Colony a forest and declined to quash the Mumbai municipal corporation's decision to allow felling of over 2,600 trees in the green zone to set up a metro car shed.

The letter states,"As we write this letter to you Mumbai authorities continue to kill the lungs of Mumbai i.e Aarey forest by clearing of trees near Mithi river bank and according to news reports 1,500 trees have already been cleared by authorities.

"Not only this but our friends are put in jail who were peacefully organising a vigil against acts of the Municipal Corporation of Greater Mumbai (MCGM) with Mumbai Metro Rail Corporation (MMRC) at the site."

The student requested the Supreme Court "to exercise its epistolary jurisdiction to protect Aarey without getting into technicalities as there was no time for preparation of a proper appeal petition and cover the scars of these young activists who are responsible citizens standing for serious environmental concerns".

It also said that students have moved the apex court as the Bombay High Court rejected the bail plea of 29 activists who had participated in the "peaceful vigil" against the tree-felling and have been detained by Mumbai Police.

The letter has alleged that the student-activists were abused and manhandled by the Mumbai Police which has booked them for offences of 'assault on a public servant to deter him from discharging his duty' and 'unlawful assembly' under the IPC.

According to the letter, Aarey forest is located adjacent to the Sanjay Gandhi National Park and has five lakh trees.

The trees were proposed to be cut for Mumbai metro-3 project and specifically for construction of a car shed, it said and added the high court refused to recognise Aarey as a forest or declare it as an ecological sensitive issue because of jurisdictional limits.

The police on Saturday imposed Section 144 of the Criminal Procedure Code in Aarey, restricting movement and gathering of groups, and cordoned off the area.