Environment

Singapore is located between latitudes 1°09’N and 1°29’ N and longitudes 103°36’ E and 104°25’ E.

The main island of Singapore is about 49km from east to west and 28km from north to south with a coastline of 224km. The total land area of Singapore is approximately 744.3km² as at end December 2025. The figures are based on 2.515m High Water Mark cadastral survey boundaries.

Singapore is generally flat, with much of the island lying within 15m of sea level. The highest point of the island’s surface reaches 164 m.

Singapore can be geographically divided into three major areas – the central hilly area with heavy deposits of granite in Bukit Timah, Bukit Panjang, Bukit Mandai and Bukit Batok; the western undulating area comprising Mount Faber Ridge and Pasir Panjang Ridge; and the eastern coastal area consisting of alluvium and sediment stretches from Katong to Bedok and Changi.

The ambient air quality in Singapore is continuously monitored by the National Environment Agency (NEA) through a network of 23 fixed air quality monitoring stations located across 5 regions of Singapore. The hourly concentrations of air pollutants, namely Sulphur Dioxide (SO2), Particulate Matter smaller than 10 microns (PM10), Particulate Matter smaller than 2.5 microns (PM2.5), Nitrogen Dioxide (NO2), Carbon Monoxide (CO) and Ozone (O3), are used to compute the Pollutant Standards Index (PSI). The 24-hour PSI is published on the NEA and haze websites, as well as on the myENV app.

Singapore’s ambient air quality is described as ‘Good’, ‘Moderate’, ‘Unhealthy’, ‘Very Unhealthy’ or ‘Hazardous’ depending on the 24-hour PSI level. During the traditional dry season when Singapore’s air quality is likely to be impacted by transboundary smoke haze, NEA will publish the 24-hr PSI forecast. Members of public can refer to the 24-hr PSI forecast with the accompanying health advisories to plan for next day outdoor activities and refer to the 1-hr PM2.5 bandings and personal guide when deciding on carrying out immediate outdoor activities.

The air quality in 2024 was in the ‘Good’ and ‘Moderate’ range for 99.5% of the year.

Singapore is situated near the equator and has a tropical climate, with relatively high and uniform temperature, abundant rainfall, and high humidity. Singapore's climate is characterised by two monsoon seasons separated by inter-monsoon periods. The Northeast Monsoon occurs from December to early March, and the 
comparatively drier Southwest Monsoon from June to September.

The early part of the Northeast Monsoon (December and January) is the wetter period of the year when monsoon surges occur, which can bring prolonged heavy rain to Singapore. The later part of the Northeast Monsoon (February to early March) is usually much drier, with February being the driest month of the year.

Afternoon thunderstorms with frequent lightning are common throughout the year, especially during the inter-monsoon periods from late March to May and October to November. During the Southwest Monsoon and inter-monsoon periods, widespread heavy rain and gusty winds associated with Sumatra squalls occur occasionally.

Based on records from the Changi climate station, Singapore’s long-term (1991-2020¹) annual mean temperature is 27.8°C, with average daily maximum and minimum temperatures of 31.6°C and 25.0°C respectively. With climate change and urbanisation, Singapore’s annual mean temperature has risen at an average rate of 0.24°C per decade between 1984 and 2024. For 2024, the annual mean temperature was 28.4 °C, making 2024 one of the warmest years on record, tying with 2019 and 2016. The annual total rainfall at the Changi climate station in 2024 was 2432.0mm, 15.1% above its long-term average of 2113.3mm.

The Meteorological Service Singapore publishes the Annual Climate Assessment Report² every year. The report provides updates on Singapore’s climate trends, with descriptions of key climatic features and notable weather events that affect Singapore.

¹The World Meteorological Organisation defines climate as the average state of the weather over a period of 30 years or more. Climate statistics are based on a 30-year reference period that is updated every ten years, with 1991-2020 as the current reference period.

²www.weather.gov.sg/climate-annual-climate-reports

Waste disposed of in Singapore is broadly classified into two categories:

Domestic waste (e.g. waste collected from residential premises, markets, food retail outlets, schools and trade premises); and non-domestic waste (e.g. waste collected from commercial and industrial premises).

Singapore has in place an integrated waste and resource management system. Waste that is not segregated at source for recycling is collected and sent to disposal facilities. Waste that can be incinerated is disposed of safely through incineration at waste-to-energy plants, which are fitted with flue gas treatment systems to remove pollutants. After incineration, ferrous and non-ferrous metals are recovered from the ash residues. The remaining ashes and non-incinerable waste are then landfilled at the offshore Semakau Landfill.

Greenhouse Gas:
Greenhouse gases comprise carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulphur hexafluoride and nitrogen trifluoride.

Land Use Allocation
Land use allocation caters for housing, industry and commerce, parks and nature reserves, community, institution and recreation facilities, utilities, land transport infrastructure, and others.

Forest
Refers to any vegetation dominated by trees having the potential to grow to at least 5 metres, with a potential canopy cover of at least 30%, in an area not less than 0.5 hectares and a minimum width of 20 metres, except in settlement areas, where the minimum area must not be less than 5 hectares.

Water-Related Ecosystems Area Change
Changes in surface-water bodies and reservoir area are measured relative to a 20-year reference period (2000-2019). A positive area change represents an area gain while a negative area change represents a loss in surface area relative to the average surface area in the 20-year reference period.

Proportion Of Population Living In Slums:
Refers to individuals who suffer one or more of the following ‘household deprivations’: 1) Lack of access to improved water source, 2) Lack of access to improved sanitation facilities, 3) Lack of sufficient living area, 4) Lack of housing durability, and 5) Lack of security of tenure.

Hazardous Waste
Hazardous Waste is defined as any industrial waste which owing to its nature, composition or quantity constitutes a danger to human health or the environment or which contains or may produce pathogens of transmissible diseases.

Biochemical Oxygen Demand
Biochemical oxygen demand (BOD) indicates the amount of oxygen taken by aerobic microorganisms as they decompose  organic matter in water. It is an indicator of organic pollution.

Degree of Integrated Water Resources Management
Measures the stages of development and implementation of Integrated Water Resources Management (IWRM), which is defined as a process which promotes the coordinated development and management of water, land and related resources in order to maximise economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.

Dissolved Oxygen
Dissolved oxygen (DO) is a measure of the amount of oxygen that is present in water. This indicates how much oxygen is available to support aquatic organisms.

Total Suspended Solids
Total suspended solids (TSS) is an indicator of water clarity. It measures the mass concentration of suspended particulate material.