UPSC 2020: In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint? 1. Copper slag 2. Cold mix asphalt technology 3. Geotextiles 4. Hot mix asphalt technology 5. Portland cement Select the correct answer using the code given below:

Environment-friendly rural roads prioritise: 1) copper-slag, an industrial by-product that replaces natural aggregates; 2) cold-mix asphalt, produced without high-temperature heating, cutting fuel use and emissions; and 3) geotextiles that reinforce soil and reduce raw-material demand. Hot-mix asphalt and Portland cement are more carbon-intensive, so they are not preferred. ([vajiramandravi.com](https://vajiramandravi.com/upsc-exam/in-rural-road-construction-the-use-of-which-of-the-following-is-preferred-for-ensuring-environmental-sustainability-or-to-reduce-carbon-footprint/?utm_source=openai))