Penang's urban area is growing at twice Malaysia's national average, at 3.29 per cent per year (Masum et al, 2017). To put this in perspective, in 1960, the island's urbanized area totalled 29.5km2, almost all of it in and immediately surrounding George Town. In 2015, the urban area had spread across 112km2 and replaced the mangroves, rubber plantations, rice paddies and fishing villages along the island's northern and eastern coasts (Schneider, 2018). This rapid and intensive urban transition has put considerable pressure on the natural environment, and has had serious socio-ecological effects, including landslides and severe flooding events in 2016 and 2017. This is due to the concentration of development on the island, which is constrained by its relatively small size (293km2) and lack of developable space given that its central area consists of steep, forested hills. As such, flooding in Penang can be seen as a consequence of both the physical characteristics of the landscape and rampant urban development.

For instance, Penang's hills contain important water catchments and forest reserves which serve to mitigate flood risk, but these are nonetheless coming under increasing threat of encroaching development. This includes both legal and illegal deforestation for housing and infrastructure developments which have been combined with inadequate mitigation measures. The threat of flooding has thus been exacerbated by land use change (urbanization), which has resulted in a lack of porous surfaces to absorb excess rainfall. Penang was therefore identified as one of the deforestation hotspots in Peninsular Malaysia in 2013 (Masum et al, 2017).

However, this is not only an issue in Penang, as Malaysia as a whole has experienced an average of 143 floods per year since 2001, of which more than 90 per cent are flash floods (D’Ayala et al, 2020). Consequently, Malaysia had the highest number of people as a percentage of the total population exposed to flooding (63) among all Association of Southeast Asian Nations member states, from 2012 to 2019 (CFE-DMHA, 2019). As D’Ayala et al (2020) note, such frequently occurring floods cause a high level of threat to the personal safety of Malaysians, while also inflicting considerable damage on the country's infrastructure.