The BCA Green Mark scheme launched in 2005 by the Building and Construction Authority (BCA) is a green building rating system tailored for thetropics and sub-tropics. Based on the Green Mark scheme, BCA rolled out the 1st, 2nd and 3rd Green Building Masterplans (GBMP) to providedirections and targets for Singapore’s built environment.The 1st GBMP released in 2006 was aimed at new developments to create green buildings from the design stage through incentives, R&D and capabilityenhancement. In addition, BCA implemented the building environmental sustainability regulation requiring all new developments to fulfil the minimumGreen Mark standard since 2008. In 2009, the inter-ministerial committee set the target of “80% of the buildings in Singapore to be green by 2030”.To achieve this target, the 2nd GBMP included $100 million cash and bonus floor area incentives along with more stringent regulatory requirements,namely, minimum Green Mark standard for existing buildings, periodic energy audit and annual building energy data submission. In 2014, BCArolled out the 3rd GBMP to encourage building tenants for energy conscious behaviour and to better address occupant wellbeing. This series of effortsresulted in the number of green buildings exponentially increasing from 17 in 2005 to about 2600 today.The Green Mark criteria have also continuously evolved over the past decade, while its framework remained the same with energy efficiency being the mostsignificant factor. Energy Efficiency requirements constitute more than half of the total score in the current version 4.1 as opposed to less than 5% forIEQ. However, the 5th version of Green Mark called Green Mark 2015 introduces sustainability in a more balanced and holistic manner with onequarter of the total score allocated for occupant health and wellbeing.The revamped version strategically outlines Indoor Air Quality (IAQ) fundamentals (ventilation, filtration, source and humidity control) throughprescriptive as well as performance based requirements. Various IAQ prerequisites such as use of low VOC paint, minimum outdoor ventilationprovision, installation of MERV 14 filters are applied to all Green Mark projects to ensure good IAQ, while higher ratings must demonstrate betterIAQ through post occupancy evaluation and IAQ surveillance audits according to local standards. Green Mark 2015 also widely adopts the newSingapore Standards (SS) 2015 to promote best practices for building occupants in the areas of visual, acoustical, spatial and thermal comfort.