Why India needs biophilic cities

CHENNAI: The State government’s proposal to set up a 118-acre urban park in the erstwhile Madras Race Course in Guindy is praiseworthy. Every major city in the developed world has a large urban park, sometimes more than one.

New York City’s iconic Central Park, established in 1858, is 843 acres in area but it is only the sixth largest park of that city!

The large urban parks in the capital cities of Europe were former Royal hunting grounds that were thrown open to the public. London’s Hyde Park (350 acres) opened to the public in 1637, Berlin’s Tiergarten (520 acres) in 1742, and Madrid’s El Retiro Park (350 acres) in 1868. All the major cities in the developed world also have a good network of small neighbourhood parks.

According to the USA’s ParkScore Index, 100% of the residents of Boston and San Francisco, and 99% of the residents of Washington DC, New York City and Seattle live within 10-minute walk of a neighbourhood park. Some global cities like Singapore are striving to create an immersive experience of nature so that wherever one looks, one can find abundant greenery. This new vision is reflected in Singapore changing its moniker from ‘Garden City’ to ‘City in a Garden’.

Unfortunately, Indian cities, barring a few, have given very low priority to public green spaces in general and to large urban parks in particular. In Chennai Corporation, there are only 3 horticulturists to 350 engineers which is a good indicator of the relative importance of green infrastructure vis-a-vis grey infrastructure in the city’s scheme of things.

In Atal Mission for Rejuvenation and Urban Transformation (AMRUT), one of India’s flagship schemes for urban development, only 2% of the total allocation is earmarked for parks and gardens.

Management guru Peter Drucker said, “Only what gets measured, gets managed.” The sad truth is that we don’t even have reliable data about the extent of public green spaces in Indian cities.

We can only arrive at a rough approximation of the same from the Forest Survey of India’s ‘State of Forest Report 2021’. It treats all lands greater than 1 hectare in area with a tree canopy density of more than 10% (including urban forests, parks, gardens, orchards, avenue trees, etc.) as ‘forest cover’.

Urban psychological penalty

Due to the noise, crowding, unnatural lighting, pollution, alienation, and rapid shrinking of green and open spaces, cities tend to have elevated rates of various mental health issues compared to rural areas – a phenomenon called the ‘urban psychological penalty’.

According to international think tank, Centre for Urban Design and Mental Health, cities are associated with nearly 40% increased likelihood of depression, over 20% higher rates of anxiety, and double the risk of schizophrenia.

A growing body of research has shown that green infrastructure is one of the potential solutions to the urban psychological penalty. An article in New Scientist (March 24, 2021) stated: “Green spaces aren’t just for nature – they boost our mental health too. We’re beginning to understand just how vital access to natural space is for our mental well-being – with implications for how we design cities worldwide.”

A study in southern England by DT Cox et al (Bioscience, 2017) tested how neighbourhood green cover within 250 metres of a house correlated with the prevalence of several mental health diseases. It found that 20% green cover was the minimum threshold needed to receive a protective effect against depression, stress, and anxiety.

A study by R MacDonald et al (Nature Conservancy, 2018) of neighbourhood green cover for 245 major cities globally found that 87% of urban dwellers lived in neighbourhoods with less than 20% green cover, and were consequently at risk of the urban psychological penalty.

Harvard biologist EO Wilson popularised the term ‘biophilia’ in the 1980s to describe how humans have innate love for, attachment to, and even need for nature due to our shared evolutionary history.

Biophilia suggests that cities are more liveable when they have abundant nature, and that people are happier and healthier when they are surrounded by greenery. A key premise of the biophilic city is that nature should be at the very centre of city design and planning, not at its periphery – as it is now.

Infra toolkit

Since the supply of vacant land in cities is limited, there is a need to incorporate nature in new and creative ways into built-up sites, interstitial spaces, and degraded areas. The green infrastructure toolkit consists of…

· green roofs and green walls in buildings

· rain gardens and landscape islands (instead of paved spaces) around buildings and in parking lots

· planter boxes (instead of concrete medians) on roads

· bioswales (instead of concrete-lined drains) in streets

· more avenue trees

· pocket parks in small open spaces and urban forests in large open spaces wherever available

· constructed wetlands and dense native vegetation along the sea coast and river banks and around lakes to replace the degraded natural wetlands

Singapore has introduced a measure of greening called the Green Plot Ratio (GPR). It’s the the ratio of the area of planted vegetation to the area of the plot, with 100% mandated as the minimum requirement for new developments. In other words, each new building in Singapore should give back to nature at least what it destroyed.

For instance, Singapore’s 36-storey residential building Newton Suites has GPR of 130%, the 16-storey hotel building Parkroyal Collection Pickering has GPR of 240%, and the 27-storey mixed-use hotel and office building Oasia Downtown has GPR of a whopping 1110%.

Why sustainable infrastructure

Apart from its psychological benefits, green infrastructure provides significant economic and ecological benefits to urban communities which grey infrastructure cannot. It increases the sequestration of carbon and thereby enhances a city’s climate resilience, protects waterbodies such as rivers and lakes from storm water and agricultural pollution, increases infiltration to the aquifers, prevents soil erosion, stabilises the sea coast and river banks and mitigates the damaging effects of cyclones, tsunamis and floods, reduces the heat island effect in cities through evapotranspiration, lowers heating and cooling energy costs, cleanses the air, mitigates noise pollution, provides habitats for animals and birds and improves biodiversity, beautifies the city, and increases property values. Grey infrastructure projects are usually large-scale, expensive, and publicly funded interventions. Green infrastructure projects are mostly small-scale, decentralised interventions allowing participation by homeowners, service clubs, private businesses, and corporates. Since nearly 60% of a city’s area is likely to be privately owned, roping in non-government players is crucial.

Urban flooding

There are certain urban problems for which grey infrastructure alone is inadequate, and a hybrid grey-green approach is called for. A case in point is the problem of urban flooding.

Urban flooding occurs when cities are inundated by water due to heavy rainfall or storm surges that overwhelm drainage systems. It destroys properties, disrupts economies, undermines human well-being, and shows the concerned State governments and urban local bodies in poor light.

It’s true that climate change has raised the risk of extreme weather events such as storms, floods, droughts, heatwaves and wildfires. In recent years, a larger percentage of precipitation has come in the form of highly intense, short-duration events. But there is a second reason for urban flooding that seldom makes news and is an under-recognised threat.

The standard cement concrete and asphalt surfaces (like buildings, roads, sidewalks, driveways, and parking lots) that dominate our urban landscape are impervious to rainwater. It runs off these surfaces rather than soaking into the ground. A paved city block generates five-and-a-half times as much runoff as a natural ground of equal size.

Due to uncontrolled urbanisation, surfaces that could have absorbed and stored the storm water runoff such as waterbodies, wetlands and flood plains have also been paved over indiscriminately. A study by AG Blum (Geophysical Research Letters, 2020) showed that for every percentage point increase in impervious surface area, annual floods increase on average by 3.3%.

Why paved surfaces cause urban flooding

Thus, urban flooding is essentially a problem of impervious surfaces. It’s going to get worse due to urban sprawl – due to the low-rise, low-density, horizontal growth that is characteristic of Chennai and other Indian cities. The conventional grey infrastructure solution to this problem is to convey the storm water runoff, essentially by gravity, through expensive cement-concrete drains (called storm water drains) to the nearest canal, lake, river or sea.

Storm water drains are necessary but not sufficient, and more often than not, they are likely to underperform or fail…

· in uneven or undulating terrains,

· in low-lying areas,

· in areas far removed from the water bodies into which the storm water is to be discharged,

· due to improper taking of contour levels and shoddy construction of the drains,

· if there are any encroachments or other blocks in the storm water network,

· if the rains are heavier than what the storm water drains were designed for,

· if the network is not complete end-to-end and doesn’t lead to a water body as a disposal point, and

· if the canal, lake, river or sea are in spate, and the storm water cannot be discharged into them due to ‘backflow’

A global problem

Dissatisfaction with the recurring failures of grey infrastructure to manage urban flooding is not confined to Chennai and other Indian cities, but is global.

For example, the American Society of Civil Engineers’ Report Card for US Infrastructure 2021 gave a lowly rating of ‘D’ to its storm water network.

Storm water runoff poses not only a quantity problem but also a quality problem. It picks up sediment, garbage, oil, fertilisers, pesticides, and various other pollutants along the way and disposes them into the lake or river. It is one of the main reasons for the degradation of a city’s lakes and rivers.

Several studies have shown that any waterbody that has more than 10% impervious surface area in its watershed becomes degraded due to storm water runoff and has a drastically reduced aquatic life. In short, storm water drains are not the panacea they are claimed to be. It’s a mistake to assume that they alone can solve the problem of urban flooding.

It’s self-evident that the only way to reduce the volume of storm water runoff is to decrease the extent of impervious surfaces and increase the extent of absorbent land, especially green spaces; in other words, to make a city ‘porous’ – like a sponge.

Trees, parks, urban forests, green roofs, green walls, rain gardens, planter boxes, bioswales, riparian vegetation and constructed wetlands, which are part of the green infrastructure toolkit, serve to slow down, soak up, filter, and store most of the rainwater where it falls, mimicking the natural water cycle. Not only do they greatly reduce the quantity but they also help improve the quality of the storm water discharged to waterbodies.

Therefore, many major cities in the developed world have been employing green infrastructure in combination with grey infrastructure to manage urban flooding. Notable examples include Washington DC, New York City, Philadelphia, Portland, Vancouver, Toronto, London, Paris, Berlin, Copenhagen, Rotterdam, Tokyo, Singapore and Melbourne. Since 2014, China has been a major proponent of the ‘Sponge City Programme’, aiming for 80% of urban areas to adopt ‘sponge features’ by 2030 so as to retain 70% of the rainwater where it falls.

An action plan

· In India, there needs to be a paradigm shift from the view that ‘parks and other green spaces are a luxury’, to the view that ‘they are absolutely essential’, not only from the mental health point of view but also for the numerous economic and ecological benefits that they provide. Since cities produce nearly 80% of the greenhouse gas emissions, the battle against climate change will be won or lost in our cities. Provision of green infrastructure should be part of an overall action plan to make cities climate-resilient and sustainable.

· At present, urban flood management in India relies solely on traditional grey infrastructure (storm water drains and canals) which is inadequate to cope with the challenges. India needs to adopt a hybrid grey-green approach and launch a National Mission on the lines of China’s Sponge City Programme.

· Due to the importance of water bodies as sinks for storm water, all encroachments in them should be evicted. Mere executive or judicial fiats cannot stop fresh encroachments – they can be averted only by developing constructed wetlands with dense native vegetation around lakes and alongside river banks. These should also serve as recreational spaces with walking and cycling trails which will give the public vested interest in taking care of the water bodies.

· Each State should organise a tree census and also arrive at the actual extents of public green spaces in its Tier 1 cities (cities with a population greater than 1 lakh) every five years. The goal should be to increase urban green cover by at least 5% every five years. States should institute awards for cities that perform the best in increasing urban green cover both quantitatively and qualitatively. They should also encourage urban local bodies to earmark a minimum of 5% of their budget for green infrastructure by giving them a 1:1 or even 2:1 matching grant if they do so.

· Cities will have to introduce a variety of by-laws, orders, standards and incentives to promote green infrastructure. It should be made compulsory to plant a shade tree for every 25 feet of new building frontage. Green roofs should be mandated for all new residential, commercial, industrial, and office buildings with plinth areas greater than 2,000 square metres. Green walls should also be encouraged. Owners of buildings (existing or new) should be incentivised to attain Green Plot Ratio (GPR) of at least 100% by giving a 33% rebate of property tax.

Between 1986 and 2007, despite its population growing by 68%, Singapore’s green cover increased from 36% to 47%. According to ecologist Timothy Beatley, “It is possible to combine urban living and life close to nature. The choice between city and nature is a false choice and an unnecessary and outdated dichotomy.”

Like Singapore, Indian cities should strive to transcend this dichotomy. Biophilic urbanism should be an integral part of India’s vision of becoming a developed country by 2047.

(The author is a retired IAS officer of Tamil Nadu cadre and a former Vice Chancellor of the Indian Maritime University)