Environmental Issues MCQ — 135 Practice Questions with Answers

Explanation

The Great Smog of London (5–9 December 1952) killed approximately 4,000 people immediately (estimates reach 12,000 total) and injured 100,000+. Cold weather led to widespread coal burning; the resulting SO₂, soot, and smoke were trapped near the ground by a temperature inversion (warm air aloft preventing cold surface air from rising). This catastrophe directly led to the UK Clean Air Act 1956.

Explanation

WHO guidelines for community noise recommend a daytime outdoor residential limit of 55 dB. For night-time sleep protection, WHO recommends less than 40 dB outdoor. India Noise Pollution Rules 2000 set limits: residential - 55 dB (day), 45 dB (night); commercial - 65/55 dB; industrial - 75/70 dB; silence zones - 50/40 dB.

Explanation

Statements 1 and 3 are correct: the IPCC was established by UNEP and WMO in 1988 to provide regular scientific assessments. Statement 2 is incorrect; the corpus states that the IPCC assesses and synthesises published scientific literature rather than conducting its own primary research.

Explanation

Statement 1 is correct: the Montreal Protocol protects the ozone layer by phasing out ozone-depleting chemicals. Statement 2 is correct: the phase-out plan covers both production and consumption of ozone-depleting substances. Statement 3 is incorrect: it was signed in 1987 and entered into force in 1989, not in 1997 and 1999.

Explanation

Chronological order: (3) 1992 Rio Earth Summit - first global recognition of desertification; (1) UNCCD - adopted June 1994, entered into force December 1996; (4) Bonn Challenge - launched September 2011 (voluntary target to restore 150M ha by 2020, 350M ha by 2030); (2) Land Degradation Neutrality - adopted at UNCCD COP12, Ankara, October 2015. So: 1992 - 1994 - 2011 - 2015 = 3-1-4-2.