Waste Management and Plastic: Rules, Methods and PYQs

The correct answer is C, vegetable peel. Biodegradable waste is waste that bacteria and fungi can break down into simpler substances within a short time, and kitchen waste such as vegetable peel is the classic example; it is exactly the wet fraction that Indian cities compost or send to a biogas digester. Option A is wrong because thermocol is expanded polystyrene, a plastic that microbes cannot digest, which is why it was included among the banned single-use items. Option B is wrong because aluminium foil is a metal; it does not rot, though it can be melted and recycled again and again. Option D is wrong because a polythene bag is a plastic that only fragments into smaller pieces and finally into microplastics, and may survive in soil and water for generations. The rule to carry into the exam hall is simple: anything that once lived, such as food, paper, cotton, leaves or dung, is biodegradable, while plastic, glass, metal and thermocol are not.

The correct answer is A, yellow. The yellow category covers human and animal anatomical waste, soiled waste such as dressings and cotton contaminated with blood, expired medicines and chemical waste, and this material is destroyed by incineration, plasma pyrolysis or deep burial; nothing from the yellow bin is recycled. Option B is wrong because the red bin takes contaminated recyclable plastic, such as tubing, catheters, urine bags, intravenous sets and syringes without needles, which is autoclaved or microwaved and then shredded for recycling. Option C is wrong because the blue category is meant for broken glassware, glass vials and metallic body implants, which are disinfected, washed and recycled. Option D is wrong because white, translucent, puncture-proof containers are reserved for sharps, that is, needles, scalpels and blades. Examiners usually set this as a match-the-pair question, so remember the four colours as one set.

The correct answer is A, smaller than 5 millimetres. Microplastics are plastic particles under five millimetres across, whether they were manufactured that small, as in cosmetic microbeads and synthetic textile fibres, or were formed when larger plastic articles weathered and broke up in sunlight and waves. Option B is wrong because five centimetres describes ordinary plastic litter, not microplastic; such pieces are visible and can still be picked up by hand. Option C is wrong because fifty microns is the scale of nanoplastics and fine fibres, far below the accepted cut-off, and no convention defines microplastics that way. Option D is wrong because a five-metre piece of plastic is macro litter such as a fishing net or a sheet. The importance of the five millimetre figure is biological: below that size plankton, fish and shellfish swallow the particles, so the plastic enters the marine food chain and comes back to human beings on the plate.

The correct answer is B, methane. In biomethanation, anaerobic bacteria break down organic matter inside a closed digester where no oxygen is present, and the gas they release is mainly methane, which is what makes biogas burn with a clean blue flame and gives it its fuel value. Option A is wrong because carbon dioxide is certainly present in biogas, but as the second component by volume, not the main one; it burns no further and only lowers the calorific value. Option C is wrong because nitrogen is at best a trace in biogas, coming from air leakage rather than from decomposition. Option D is wrong because sulphur dioxide is not produced in the digester; the sulphur impurity in biogas appears as hydrogen sulphide, which must be scrubbed out because it corrodes engines and pipes. The same methane forms slowly in a covered landfill, where it is called landfill gas and is either flared or tapped for power.

The correct answer is B, Extended Producer Responsibility. Under this idea a producer, importer or brand owner stays answerable for its product after the consumer has finished with it, and must arrange to collect back and recycle an agreed quantity of packaging or equipment; the plastic waste, e-waste and battery waste rules all run on it. Option A is wrong because the Environment (Protection) Act of 1986 and the rules made under it already carry their own names, and no waste rule uses the abbreviation for them. Option C is wrong because there is no statutory register by that name; effluents are regulated by consent conditions issued by the State Pollution Control Boards under the water law. Option D is wrong because energy recovery from refuse is called waste to energy or refuse-derived fuel, not EPR. Extended Producer Responsibility is best remembered as the working form of the polluter pays principle, applied to the maker rather than to the user.

The correct answer is B, transboundary movement of hazardous wastes. The Basel Convention was adopted in 1989 to stop rich countries from shipping toxic and hazardous waste to poorer countries for cheap disposal, and it requires the prior informed consent of the receiving country before any such consignment moves. Option A is wrong because the ozone layer is protected by the Vienna Convention of 1985 and the Montreal Protocol of 1987, which phase out chlorofluorocarbons and similar substances. Option C is wrong because migratory species are covered by the Convention on Migratory Species, also called the Bonn Convention, of 1979. Option D is wrong because trade in endangered plants and animals is regulated by CITES, signed in 1973 at Washington. Learn these conventions as city and subject pairs, because that is exactly how the question is framed: Basel for hazardous waste, Stockholm for persistent organic pollutants, Rotterdam for prior informed consent and Minamata for mercury.

The correct answer is A, earthworms. Vermicomposting uses earthworms, which swallow organic waste, grind it in their gizzard and pass it out as casts that are rich in nitrogen, phosphorus and potassium, so the product is a finer and more nutritious manure than ordinary compost and is ready sooner. Option B is wrong because termites do digest cellulose, with the help of protozoa in their gut, but they are pests of wood and buildings and are never used in a composting pit. Option C is wrong because honey bees are pollinators that collect nectar and pollen and play no part in decomposition. Option D is wrong because blue-green algae, or cyanobacteria, fix atmospheric nitrogen in paddy fields and are used as a biofertiliser, which is a different service altogether. Remember that the earthworm is called the farmer's friend for exactly this reason, and that vermicompost is a decentralised method well suited to housing societies and schools.

The correct answer is B, decomposition of waste by heating in the absence of oxygen. In pyrolysis the waste is heated to a high temperature in a closed chamber from which air is kept out, so the material does not burn but breaks into a liquid oil, a solid char and a combustible gas, all of which can be used as fuel or feedstock. Option A is wrong because burning in excess air is incineration, which leaves ash and releases heat directly and needs careful cleaning of the flue gases. Option C is wrong because decomposition by earthworms is vermicomposting, a biological process that works at ordinary temperatures. Option D is wrong because compaction in a lined pit describes a sanitary landfill, where the waste is merely stored under a soil cover while it slowly generates methane and leachate. The prefix pyro points to heat and lysis to breaking, so the word itself carries the definition.

The correct answer is B, 2 October 2014. The mission was launched on the 145th birth anniversary of Mahatma Gandhi, whose insistence on sanitation the campaign invokes, and it runs in two wings, one for urban areas and one for rural areas. Option A is wrong because 15 August 2014 was the Independence Day speech in which the campaign was announced from the Red Fort, but the formal launch came later that year. Option C is wrong because 26 January is Republic Day and carries no connection with the sanitation mission. Option D is wrong because 5 June is World Environment Day, marked since 1973 after the Stockholm Conference of 1972, and is not the launch date of any Indian sanitation programme. Two more dates are worth carrying with this one: 2 October is observed as Swachh Bharat Diwas every year, and cities have been ranked annually under the Swachh Survekshan cleanliness survey since 2016.

The correct answer is A, 1 July 2022. From that date the manufacture, import, stocking, distribution, sale and use of a listed set of single-use plastic articles became an offence across the country; the list covers earbuds with plastic sticks, plastic sticks for balloons and flags, candy and ice-cream sticks, thermocol used for decoration, plates, cups, glasses, cutlery, straws, stirrers and the wrapping film around sweet boxes and invitation cards. Option B is wrong because 2 October 2019 saw a nationwide appeal and drive against single-use plastic, but no ban was notified on that date. Option C is wrong because the notification of 2021 dealt with carry bag thickness and set the ban date a year and a half ahead, giving the industry time to change over. Option D is wrong because no fresh nationwide list took effect in August 2023. Pair this date with the thickness rule: 75 microns from 30 September 2021 and 120 microns from 31 December 2022.