Chapter 16: Environmental Issues

Ans: Yes, carpets and curtains/drapes that are laid on the floor or hanging on the wall surfaces could greatly reduce noise levels. This is because these objects are made up of fibers and fibers can absorb sound waves acting as sound barriers and thus, reduce the sound level. On the other hand, the carpets act as muffling devices and absorb sounds at a moderate level.

Ans: The technology which is used to run some vehicles on a dual-mode like petrol and compressed natural gas (CNG) is called hybrid vehicle technology. These vehicles run either on petrol or CNG and can efficiently run on any one of these two fuels at a time. This is called a green fuel as it helps reduce environmental pollution and also to conserve petroleum fossil fuel which is non-renewable.

Ans: Yes, it is completely true that if the dissolved oxygen level in a water body drops to zero, the water will become septic. The absence of oxygen in water means water will no longer be able to support life in it because the aquatic plants and animals living there use this dissolved oxygen for respiration. When sewage water is discharged into a water body, microorganisms efficiently feed on organic impurities and grow excessively. In this process, they consume most of the oxygen in the water for respiration and this reduces the oxygen level to zero.

Ans:  Carbon dioxide is one of the potent greenhouse gases and is produced by the burning of fossil fuels and other organic matter in presence of oxygen. The excess level of carbon dioxide in the atmosphere causes a greenhouse effect, absorbs heat and results in global warming.

Ans: Trees and shrubs are grown near the boundary walls of buildings, along roadsides and around residential areas to help in reduction of noise pollution. These trees serve as noise screens and also as dust catchers, namely a sound barrier.

Ans: It is a well-established fact that any conservation efforts in a biodiversity-rich area give better results. The hilly areas have a better and more dense biodiversity than the  plains because of less human  intervention. This is the reason that the National Forest Commission of India recommended a relatively larger forest cover for hills than for plains.

Ans: Slash and burn agriculture is an ancient practice which is still practiced by the tribal people in today’s time but due to increasing population and more land being used right now, this practice is becoming an environmental disturbance. Earlier, a proper recovery time was provided to the ground used to recover when a particular patch of land was left fallow but now, due to increased population and industrialization, this period of recovery has been greatly reduced, and if the forests are given proper recovery time after using any part of the land then it will become eco-friendly again. Another idea is to not burn the remains of the land and instead till them with the soil again to enrich the soil with plant remains.

Ans: The motive behind “Joint Forest Management Concept” implemented by the Government of India” was that the involvement of local communities in forest management will lead to greater change and acceptability. In the past, it was observed that when the local people were excluded from forest management, they felt alienated and revolted against the changes occurring in their local area. This always resulted in a clash of interests between locals and government leading to failure of projects. Involvement of the local community produces better results in terms of conservation in a sustainable manner and efficiency.

Ans: Snow blindness, also known as arc eye is a painful eye condition which is brought on by excess exposure of eyes to ultraviolet light. When too much UV light hits the transparent outer layer i.e., cornea of your eyes, it gives your cornea a sunburn which leads to this condition.

Ans: DDT is a potent pesticide and an organic compound which was initially thought to be of no harm but has been found out to accumulate. The accumulation of DDT in various organisms at different trophic levels is called biomagnification and is a major problem in the bird population. DDT in a bird's body leads to the thinning of eggshells of birds which kill the newborns before the egg has even hatched which causes a decline in the bird population.