NEW DELHI: While the issue of cutting down of

trees

at the Aarey forest in Mumbai to build a

shed has taken the centre stage, the Delhi Metro—which has a network of around 377 km has had to face similar challenges in the capital during its expansion. Until phase-III completion, the Delhi Metro Rail Corporation (DMRC) has had to not only cut trees, but also modify their alignment plans to avoid major monuments as well as level out a ‘closed landfill’ site during Phase-I to construct a depot. From Phase I until Phase III, while DMRC had been provided permission to fell as many as 56,307 trees, it managed to

12,580 trees. As many as 43,727 trees were felled which it said could not be navigated or manouvered through.

“An environmental impact assessment is required for every project. When we begin work according to the detailed project report (DPR), we can make some adjustments on the ground, and the alignment can be modified slightly if we realise a tree can be saved. In cases where that is not possible, the tree has to be felled,” said a metro spokesperson.

DMRC said that it had also experimented with tree transplantation which is still being carried out in certain places. “The tree can only be transplanted in a 5-km radius so that its chance of survival is high. The overall survival rate has been low,” said Anuj Dayal, spokesperson, DMRC.

Each time a tree is felled, DMRC is required to pay a compensation to the Delhi forest department which in turn carries out compensatory afforestation in the ratio of 10:1, that is 10 saplings for each tree cut. According to DMRC data, a total of 5,35,150 saplings have been planted till date by the forest department which is also monitored by the DMRC. “The survival rate has been over 80%,” said a spokesperson.

In terms of carrying out construction, DMRC said the major challenges they faced centred around navigating through densely populated residential areas and monuments.

During Phase-I, the metro had to build its depot for its underground corridor at a closed landfill site near Khyber Pass by flattening the area, removing the landfill waste and replacing it with fresh soil.

“Provisions for flaring of methane gas, which might have accumulated over a period of time, were also made. Without the depot, construction work would not have progressed or been possible,” said the DMRC.

Meanwhile, tunnelling work of the heritage line which passes near Jantar Mantar (233m), Agarsain ki baoli (189m), Khooni Darwaza (24.6m), Delhi Gate (100m), Feroz Shah Kotla (121m), Shahi Sunehri Masjid (103m) and Lal Qila (118m) had to be carried out by shifting the alignment of the up and down-lines.

Civil work near residential colonies, and Kailash colony in particular, has been an issue due to noise pollution. “The construction near Qutub Minar and other monuments, especially on the heritage line was difficult as we had to navigate and adjust the metro lines in order to avoid archaeological structures and damage in their vicinity,” said the DMRC.

In terms of de-watering areas to build underground metro lines, officials said that DMRC in Phase-I opted for an approach of giving the water to the Chandrawal Water Works. It also used the water to revive Sarpakar lake in north Delhi. “From Phase II onwards, we started recharging the groundwater in the area again,” said the DMRC spokesperson.

According to an audit, the DMRC said that it had offset CO2 to the tune of 3.5 million tonnes so far, with the figure likely to increase further after expansion. The Delhi Metro has 274 stations across its 377-km long network.