Taking a cue from the pillar-based vertical gardens in Singapore and Mexico city, the Prime Minister’s Office (PMO) has asked the Ministry of Housing and Urban Affairs, and the Ministry of Environment to develop vertical gardens across the city to curb air pollution.

In India, the Kochi Metro was the first among the metrorail corporations to build vertical gardens in January 2017. These gardens would help keep a check on the increasing air pollution. These gardens will also reduce urban heat island effect and smog, purify polluted air, act as a sound-proofing barrier, create a healthy habitat for birds and insects and increase real estate value.

Sources in the Ministry of Housing and Urban Affairs told The Pioneer that the PMO has called a high-level meeting on April 20, on measures being taken by the agencies to check pollution level in Delhi.

“At the meeting, the PMO has advised the HUA Ministry and the Ministry of Environment to develop and promote vertical gardens in Delhi to check air pollution, especially dust pollution,” sources added.

According to sources, a presentation was also made before the PMO on how vertical gardens help purify polluted air and reduce urban heat island effect and smog.

Delhi generates 131 tonnes of dust everyday, according to the Union Environment Ministry, making airborne dust one of the largest components of PM 2.5 (microscopic, respirable particles) in the Capital. According to an IIT Kanpur report, road dust makes up over 50 per cent of the total PM10 particles and about 38 per cent of PM 2.5 particles.

PM 2.5 and PM 10 are the most dominant pollutants in Delhi’s air. These ultrafine particulates, which can measure up to 30 times tinier than the width of a human hair and reach the bloodstream of a person through the respiratory system, pose serious health risks.

To begin with, vertical gardens have been developed at the junction of Sikandra Road, Tilak Marg and Mathura Road as a pilot project in the national Capital. Vertical garden is also being developed at Delhi-Meerut Expressway and Nizamuddin Bridge. In fact, a four-storey high vertical garden can remove 130 grams of particulates from the air, filter 40 tonnes of greenhouse gases and process over 15 kg of harmful heavy metals.

Vertical gardens are grown along walls or pillars, with the help of wooden frames or similar support systems. The plants on the vertical garden are grown without soil.

The Delhi Metro recently transformed eight drab-looking pillars along its elevated Blue Line between Mandi House and Pragati Maidan stations into beautiful green vertical gardens. “The once lacklustre pillars are now covered with a mesh frame, where plants in small pots are mounted nearby, to give it a classic vertical garden look,” said officials of the HUA Ministry.

The New Delhi Municipal Council (NDMC) and South Delhi Municipal Corporation (SDMC) have also started developing such gardens in their areas. The South MCD has decided to develop vertical gardens under all flyovers. North MCD is also developing vertical garden at Rani Jhansi Road flyover which is under construction.

“Vertical gardens can be used to partition spaces, block off windows that look out at a less than desirable view and are far cheaper than creating a horizontal garden of similar size, despite the initial investment. People, especially those living in high rises, are placing plants such as dwarf date palm, Chinese evergreen, flamingo lily, even the humble rubber plant, in their homes for better air quality,” said officials of the HUA Ministry.

The IIT Kanpur report further stated that PM2.5 nitrate particles formed from nitrogen oxides and sulphate particles formed from sulphur dioxides can be 25 per cent of the total PM2.5 load in the city. Both nitrates and sulphates are classified as ‘secondary particles’, which are formed due to the reaction of gases such as sulphur dioxide (SO2) and oxides of nitrogen (NOx) emitted from vehicles, thermal power plants and industries.

Source: 23 April, 2018, The Pioneer