[4] The marsh contains several rare or endangered and threatened species and acts as a forage and breeding ground for thousands of migratory birds from various places within and outside the country.

[6][7][8] A 2018 study showed that about 60 percent of the native species in the wetland, including hoorahgrass (Fimbristylis), dwarf copperleaf or Ponnanganni keerai (Alternanthera sessilis), floating lace plant or kottikizhangu (Aponogeton natans), wild paddy (Oryza rufipogon), crested floating heart (Nymphoides), and nut grass (Cyperus), have been replaced by invasive species.

[9] The marshland is located along the Coromandel Coast south of the Adyar Estuary, serving as an aquatic buffer of the flood-prone Chennai and Chengalpattu districts.

The entire landscape comprises a coastal plain with intermittent and overlapping habitat types of cultivated land, wetlands and scrub forests.

[11] Spread over 50 square kilometres (19 sq mi) at the time of Independence in the 1940s, about 90% of the wetland was lost as the city expanded and it continued shrinking at an alarming rate.

The marshland has shrunk over the last four decades following the creation of residential areas around it, including Perungudi, Siruseri, Pallikaranai, Madipakkam, Taramani and Velachery.

Other estuarine fauna present at the marsh includes the windowpane oyster, mud crab, mullet, halfbeak and green chromide.

[4] The marshland experienced several major construction activities, ranging from the National Institute of Ocean Technology, the Centre of Wind Energy Technology, Chennai's Mass Rapid Transport System, and flyovers to construction of buildings for educational institutions, IT parks, restaurants, shopping malls, and hospitals, which affected free flow of water.

This has resulted in leaching of heavy metals in the marsh, including chromium, lead, iron, manganese, cobalt, nickel, copper, zinc and cadmium from the 172-hectare Perungudi dumpyard developed by the city corporation.

Official statistics reveal that, in the absence of source segregation of waste, the dumpyard is eating into 4 hectares (9.9 acres) of marshland every year.

[28][29] A research by the Anna University revealed a large quantity of metallic sedimentation discharged from the Perungudi dumpyard being deposited in the marshland, affecting its biodiversity.

[30] In 2002, the Tamil Nadu Pollution Control Board commissioned a study to find out the total area of the marsh and its habitat quality and suggested interventional methods.

On 20 February 2003, the Kancheepuram district collector issued a gazette notification announcing that 548 hectares (1,350 acres) of the marsh area was classified as Protected Land.

However, researchers suggested that an additional 150 ha on both sides of the Thoraipakkam–Tambaram road bisecting the marsh be declared a reserve forest as birds, especially several varieties of ducks, came there for feeding.

Anticipating the obstruction of the water flow from north to south by the growing garbage mounds, the government directed the civic body to transfer 150 hectares (370 acres) to the forest department.

After this, the state government will acquire patches of land in the northern (adjacent to Velachery–Tambaram road) and southeastern parts of the marshland, measuring about 127 hectares (310 acres), to protect the ecosystem in its totality from becoming an open dumpyard.

[33] Save Pallikaranai, a campaign for protecting an ecologically sensitive environment despite urban pressures, has achieved significant success owing to people's participation, sustained media support and a responsive government.

There was a proposal to turn the Pallikaranai marsh into a wetland centre by networking with international agencies to attract funds for its protection and restoration.

In 2011, an adaptive management plan for the Pallikaranai marshland estimated at a cost of ₹ 150 million was prepared by Chennai-based NGO called Care Earth, an organisation working towards ecological conservation,[34] which has been sent to the Union Ministry by the state department and is pending for approval.

In addition, there is a proposal for creating roadside parks, installing signage, and conducting awareness camps during the project implementation period at a cost of ₹ 4 million as part of the initiative.

The Forest Department, which plans to undertake restoration of the eco-sensitive Pallikaranai marshland, will get 421 acres (170 ha) for the purpose from the Chennai Corporation.

[5] In March 2018, the state government announced that it would commence the eco-restoration of 695 hectares of the wetland under the National Adaptation Fund for Climate Change to be implemented over five years from 2018 to 2023 at a cost of ₹ 1656.8 million.

[10][15] On 19 March 2011, a fire started on a patch of land opposite Kamakshi Memorial Hospital around 4 pm local time and spread to 15 locations in the marsh.