The 3.2km-long Singapore River has been the lifeline of Singapore for more than 150 years. In the years following independence, the river remained heavily polluted, with garbage, industrial waste and even oil spills a common sight (and smell).

Mr Lee sought to change that in 1977, saying that keeping Singapore’s waterways clean had to be a priority. He then set a target for the then Ministry of Environment to clean up the Singapore River in 10 years, which was met.

As Ms Jessica Tan, MP for East Coast GRC, said at an event last year: “When I was young, my parents used to say, ‘As smelly as the Singapore River’. They can no longer say that, thanks to Mr Lee.”

His legacy of clean waterways lives on not just in the Singapore River but across the island’s water bodies, thanks to the PUB’s Active, Beautiful, Clean Waters programme, which has transformed urban canals into naturalised recreational spaces for the community.

A boom in air travel in the 1970s stretched the Republic’s former airport at Paya Lebar to its limits. A British aviation consultant proposed an expansion of the airport, a move that would save the government on land acquisition and resettlement costs. But Mr Lee raised concerns about the excessive noise pollution an expanded Paya Lebar Airport would impose on the city centre. Believing that a Changi site would manage noise better, he appointed then-chairman of the Port of Singapore Authority Howe Yoon Chong to a chair a top-level committee to make a reappraisal. After much deliberation, they reported that Mr Lee’s idea was feasible and within six years, Changi Airport opened with a single terminal and runway. The decade saw unprecedented economic growth and by the new millennium, the airport had expanded to include a second terminal and runway. Last year, the airport handled more than 55 million air movements, a record in its 35-year history, cementing Singapore’s status as an international air hub.

In 1987, Mr Lee Kuan Yew had envisioned the damming of Singapore’s 350-metre wide Marina Channel to create a freshwater reservoir. That very dam – named Marina Barrage – was officially unveiled in 2008, along with the city’s first urban reservoir, Marina Reservoir. Along with Punggol and Serangoon reservoirs, it increased Singapore’s water catchment area to two-thirds of Singapore’s land area in 2011. Mr Lee became Prime Minister when the national water supply was a contentious issue, and in 2008 he had said that “every other policy has to bend at the knees for our water survival”.

At the advice of Dutch economist Albert Winsemius, Mr Lee and his team established a major industrial estate in Jurong. Previously a mangrove swamp, the area was transformed into a thriving industrial area from 1960. The area showed Singapore’s emphasis on manufacturing, which in 1975, surpassed trade to become the largest sector in the Republic’s economy. Mr Lee was also instrumental in the development of the nation’s first petrochemical complex on Pulau Ayer Merbau, which opened in 1989. The complex eventually became a part of Jurong Island, which has helped Singapore establish itself as the region’s leading oil trading hub. According to the Economic Development Board, the oil industry accounts for 5 per cent of Singapore’s gross domestic product.

Mr Lee was a familiar face at the Singapore Zoological Gardens, visiting the site nearly every year with his family. But he was more than just a casual visitor; Mr Lee often left the Zoo with suggestions on how to improve it further. He once asked for slow-growing jungle trees to be planted to improve the area’s diversity. Acting on the suggestion, Wildlife Reserves Singapore planted 1,000 such trees over three years.

Mr Lee was also concerned about incidents that happened at the zoo: The 1974 escape of Congo the hippopotamus, which eluded keepers for 52 days, particularly upset him, as he was worried that the animal would pollute nearby water bodies.

In his speech at the Zoo’s 20th anniversary dinner in 1993, Mr Lee said: “I have made many visits to the Zoo in the last 20 year... and the reason I come back is because each time it gives me the impression of being well kept, well maintained, receiving a lot of care and attention. I think it symbolises the kind of effort Singapore has to make if it is going to remain what it has been.”

Mr Lee Kuan Yew was also known as Singapore’s chief gardener, as he had been the driving force behind the Garden City concept. The Republic’s greening movement kicked off in 1963, when Mr Lee planted a Mempat tree along Farrer Circus. He believed lush greenery amid a litter-free environment would attract both foreign investors and tourists to Singapore.

In 2012, PM Lee Hsien Loong opened Gardens by the Bay, a billion-dollar attraction covering 101 hectares of reclaimed land and dedicated to the world’s flora. At a special preview of the Gardens’ Flower Dome in 2011, Mr Lee termed the attraction a world-class garden that would “showcase what we can do to bring the world of plants to all Singaporeans.” In a later statement, he said that concrete buildings, tarmac and pavements would dull the streets, while trees and flowers would make Singapore more pleasant to live in.

Punggol Eco-Town is an estate designed to promote sustainable living, the first of its kind in Singapore. It is home to HDB’s first eco-precinct, Treelodge@Punggol, which is noticeably smaller and surrounded by green spaces. It also includes an integrated public transport network for residents, as part of its efforts to be environmentally-friendly.

Formerly a fishing village, the waterfront town also has a waterway traversing through the town, named My Waterway@Punggol.

In 1974, Mr Lee asked the HDB to improve the quality and vary the design and landscaping of new towns to add distinctiveness and character by “exploiting unique site features such as undulating terrain and ponds”, an idea that was incorporated into the concept of Punggol Eco-Town.

Singapore’s largest offshore island is now a symbol of its military strength, thanks to the Basic Military Training Centre located there. Many conscripts of the Singapore Armed Forces (SAF) pass through the island and its training sites, beginning a 9-week long induction into military life as part of their National Service (NS) journey.

Mr Lee, together with former defence minister Goh Keng Swee, was instrumental to the introduction of NS in 1967. As Prime Minister Lee Hsien Loong recalled at Mr Lee’s funeral last year, NS succeeded because Mr Lee had personally convinced parents to entrust their sons to the SAF. “He succeeded, first because he led by example. His two sons did NS just like every Singaporean son; in fact my brother and I signed up as regulars in the SAF “tan jiak bing” (in Hokkien), and we took up SAF Scholarships. Secondly, people trusted Mr Lee, and believed in the Singapore cause. Therefore today, we sleep peacefully at night — confident that we are well protected.”