Environmental activists and retired judges say that Prime Minister Narendra Modi's visit to Isha Foundation in Coimbatore to unveil the 112-foot face of Lord Shiva would legitimise illegal constructions by the organisation.

Modi will unveil what is said to be the largest sculpture of the face of Lord Shiva on the planet, at 6 p.m. on Friday, the Mahashivaratri day.

"Several cases are pending in Madras High Court and the National Green Tribunal (NGT) against Isha Foundation for carrying on unauthorised construction on a large scale," said M. Vetri Selvan, an advocate and a member of Poovulagin Nanbargal, an environmental NGO.

The Isha Foundation was founded by Sadhguru Jaggi Vasudev.

"The state government authorities have even issued demolition notices for constructed buildings to Isha Foundation. The foundation did not secure building permission from the Hill Area Conservation Authority (HACA) for various constructions," Selvan added.

He alleged that even the 112-foot face sculpture of Lord Shiva does not have necessary permission.

Justice (retd) D. Hariparanthaman of the Madras High Court told the media on Wednesday that the Isha Foundation has illegal constructions measuring several lakhs of square feet and Modi's visit to that place may hinder justice.

According to Hariparanthaman, the Town and Country Planning Department itself has told the Madras High Court in 2013 that 13 lakh sq.ft is the extent of illegal construction by Isha Foundation.

A notice to stop work was issued to the foundation in December 2012.

"The visit of the Prime Minister to Isha Foundation, which is mired in illegalities in the form of illegal buildings facing demolition notices issued by the government of Tamil Nadu, may amount to interfering with the administration of justice," Selvan added.

Selvan said Poovulagin Nanbargal has written to Modi, requesting him not to participate in the Mahashivaratri celebrations at Isha Foundation on February 24, organised by Sadhguru Jaggi Vasudev.

The letter says he has illegally constructed buildings to the extent of about 1,25,000 sq.m. at the Velliangiri Hills in Coimbatore.

According to Selvan, the various pending cases speak volumes about the illegalities committed by Isha Foundation at various levels.

"The day-to-day activities of Isha Foundation, as admitted by the authorities of the State of Tamil Nadu in the writ petitions, are within the realm of violation of various statutes including the Tamil Nadu Town and Country Planning Act, Environment (Protection) Act, and the Forest (Conservation) Act," Selvan said.

When contacted by IANS, an official of Isha Foundation dismissed the allegations, saying that there is no illegality in the constructions.

In its blog on February 18, 2017, Isha Foundation said: "The accusations laid down in the petitions filed against Isha Foundation in the Madras High Court are frivolous and a compilation of twisted allegations."

"We have obtained the approval of the necessary authorities, including the District Collector, Coimbatore, the Forest Department and BSNL," the foundation said.

The National Green Tribunal on February 17, 2017, admitted an application filed by Selvan for a permanent injunction restraining Isha Foundation from conducting the Mahashivratri festival and other cultural extravaganza within the buffer-zone of the adjacent forest.

A structural stability certificate from a government certified engineer has also been obtained for the 112-ft sculpture. "A No Objection Certificate from the District Collector of Coimbatore for using wetlands for non-agricultural purposes has also been obtained. So the question of violation does not even arise," the blog by the foundation adds.

The Tribunal has listed the hearing of the application for March 23, 2017.