A purity test is a self-graded survey that assesses the participants’ supposed degree of innocence in worldly matters (sex, drugs, deceit, and other activities assumed to be vices), generally on a percentage scale with 100% being the most and 0% being the least pure.

Singapore has implemented various measures to maintain good air quality, and the National Environment Agency (NEA) regularly monitors the Pollutant Standards Index (PSI) to assess air pollution levels. The PSI measures six air pollutants: sulfur dioxide, nitrogen dioxide, particulate matter (PM10 and PM2.5), carbon monoxide, and ozone.

During periods of haze caused by forest fires in the region, Singapore’s air quality can be affected. The PSI readings fluctuate based on the concentration of pollutants, and they range from “Good” (0-50 PSI) to “Hazardous” (above 300 PSI). It’s important to refer to the NEA or other authoritative sources for the most accurate and current information regarding air quality in Singapore.