Option 1: Thermal power plants are known to produce a significant amount of non-biodegradable waste. This is due to the nature of their operations, which involve burning fossil fuels such as coal or oil to generate electricity. As a result, thermal power plants emit various pollutants, including non-biodegradable substances like ash and fly ash.

Option 2: While food processing units can generate some non-biodegradable waste, it is generally less compared to thermal power plants. Food processing facilities primarily deal with organic materials, such as fruits, vegetables, and meat, which tend to be biodegradable.

Option 3: Textile mills can also produce non-biodegradable waste in the form of chemicals used in the dyeing and finishing processes. However, their waste output is typically lower than thermal power plants.

Option 4: Paper mills primarily produce organic waste, as they deal with wood fibers to manufacture paper. Therefore, they generally produce less non-biodegradable waste compared to thermal power plants.

Overall, while all the options listed can generate some non-biodegradable waste, thermal power plants are known to produce the most significant amount of such waste. Alert - Correct answer should be: All of the above options can produce non-biodegradable waste, but thermal power plants