What's the difference between PVC and LS0H cables

Polyvinyl chloride (PVC) cable has a jacket that gives off heavy black smoke, hydrochloric acid, and other toxic gases when it burns.

Low Smoke Zero Halogen (LS0H) cable has a flame-resistant jacket that doesn't emit toxic fumes even if it burns.

LS0H cables usually cost more than the equivalent PVC cable, and certain types are less flexible. LS0H cable does have some restrictions. According to CENELEC standards EN50167, 50168, 50169, screened cables must be halogen free. However, no similar regulation yet applies to unscreened cables.