Assertion: In a sanitary landfill wastes are dumped in a depression or trench after compaction and covered with dirt everyday.
Reason: There is a danger of seepage of chemicals from these landfills polluting the underground water resources

The basic characteristics of a modern landfill site i) Methods to contain leachate such as lining clay or plastic liners. ii) Compaction and covering of the waste to prevent in from being blown by wind. iii) Installation of a landfill gas extraction system to extract the gas for use in generation of power. (iv) This is ideal for disposal of radioactive wastes

Read the passage given below and answer the question: Biopolymers are polymers that are generated from renewable natural sources, are often biodegradable and nontoxic. They can be produced by biological systems (i.e. microorganisms, plants and animals), or chemically synthesized from biological materials (e.g., sugars, starch, natural fats or oils, etc.). Two strategies are applied in converting these raw materials into biodegradable polymers: extraction of the native polymer from a plant or animal tissue, and a chemical or biotechnological route of monomer polymerization. Biodegradable biopolymers (BDP) are an alternative to petroleum-based polymers (traditional plastics). Some BDP degrade in only a few weeks, while the degradation of others takes several months. In principle the properties relevant for application as well as biodegradability are determined by the molecular structure. According to the American Society for Testing and Materials, biopolymers are degradable polymers in which degradation results from the action of naturally occurring microorganisms such as bacteria, fungi and algae. Polylactic acid (PLA) is an example of biopolymer. It is a thermoplastic polyester. Generally, there are two major routes to produce polylactic acid from the lactic acid (CH_(3)CH(OH) COOH) monomer. The first route involves condensation-water removal by the use of solvent under high vacuum and temperature. This approach produces a low to intermediate molar mass polymer. An alternative method is to remove water under milder conditions, without solvent, to produce a cyclic intermediate dimer, referred to as lactide. This intermediate is readily purified by vacuum distillation. Ring opening polymerization of the dimer is accomplished under heat, again without the need for solvent. By controlling the purity of the dimer it is possible to produce a wide range of molar masses .PLA is a good material for production of clothing, carpet tiles, interior and outdoor furnishing, geotextiles, bags, filtration systems, etc. The primary biodegradability of PLA was tested using hydrolysis tests at various composting temperatures and pH. It was demonstrated that composting is a useful method for PLA biodegradation. The degradation rate is very slow in ambient temperatures. A 2017 study found that at 25 ^(@)C in sea water, PLA showed no degradation over a year. As a result, it is poorly degraded in landfills and household composts, but is effectively digested in hotter industrial composts. (source: Flieger, M., Kantorová, M., Prell, A., Rezanka, T., & Votruba, J. (2003). Biodegradable plastics from renewable sources. Folia Microbiologica, 48(1), 27 44. doi:10.1007/bf02931273) In the question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage. Assertion: PLA is poorly degraded in landfills. Reason: The degradation rate of PLA is very slow in ambient temperatures.

India generates at least 25,940 tonnes of plastic waste daily, equivalent to the weight of around 4,300 elephants. Of this, about 60% gets recycled, according to the Union environment ministry. The rest gets dumped in landfills, clogs drains, goes into the ocean as micro-plastics, or is burnt, leading to air pollution. In the absence of a proper waste management system, the plastics that get recycled are often dirty, which makes the re-cycling process water-intensive and expensive. “It is the process of cleaning the plastics before recycling that makes it resource intensive. A lot of water is required to wash the collected plastics, especially if it is oily or greasy as it has to be cleaned with a solvent,” said Dr Suneel Pandey, director of environment and waste management, The Energy and Resources Institute (TERI. Experts say proper waste collection and management is at the core of ensuring more plastics get recycled instead of ending up in landfills and oceans. Researchers from various institutes have come up with innovative ways to utilise the plastic waste that cannot be recycled further or are unrecyclable. At IIT Delhi, a group of chemical engineers are working on chemically breaking down plastics to its smaller hydrocarbon molecules and then synthesising diesel out of it. The process uses packaging material, Polyethylene terephthalate (PET bottles, polystyrene, and multi-layer packaging. The fuel produced can currently be used as a blend in stationary diesel machines like generators and needs further testing and standardisation to be used as commercial diesel in vehicles. A mix of plastic and stone has been used to create a block that can be used in flooring. A CSIR laboratory also used shredded plastics, chemically treated it and mixed with fillers to make tiles. A German chemical producer called BASF is also breaking down waste plastic and using it as raw material for chemicals, instead of using material derived from fossil fuels. One cost-effective solution was developed by Dr Rajagopalan Vasudevan, professor at Thiagarajar College of Engineering in Madurai. The National Highways Authority of India is currently scaling up his technology to use plastic waste in making roads. He came up with the idea of mixing plastic waste with Bitumen used for constructing roads in 2001. “That year the Tamil Nadu government had planned to ban plastic and my concern began with the more than 1 lakh people employed by the industry. Since plastic is derived from petroleum just like Bitumen, I thought of using it for road construction. The result, not only plastic waste was getting utilised, the roads were cheaper and steadier,” he said. The plastic waste does not have to be segregated and even multilayered plastics can be used in the mix. “All we need to do is collect the waste, dry it out and use it,” he said. The construction of every kilometre of road required nine tonnes of Bitumen and one tonne of plastic waste. This means for every kilometre of road, one-tonne Bitumen is saved, which costs about ₹30,000. What has been developed by Dr Rajagopalan Vasudevan, professor at Thiagarajar College of Engineering in Madurai?