पर्यावरण अध्ययन (EVS) के NCERT प्राथमिक विद्यालय के पाठ्यक्रम के अनुसार, निम्नलिखित में से कौन-सा एक उप-विषय (सब-थीम) है?

Prolonged occupational exposure to excessive noise from heavy machinery without hearing protection causes noise-induced hearing loss. Excess noise is categorized as a:

Long-term exposure to indoor air pollutants, such as smoke from burning biomass fuels, significantly increases the risk of developing chronic respiratory conditions like: