Complex sentence: All of these components will react under rigorous conditions, for example, the high temperature in the incinerator or degradation under UV light in landfills, to release harmful gases that causes significant environmental pollution.
Split into simpler sentences: All of these components will react under rigorous conditions, for example, the high temperature in the incinerator. Also, degradation under direct UV light occurs in landfills, to release harmful gases that causes significant environmental pollution.