To ‘incinerate’ mean to burn something completely – ie. until it cannot be burnt any further. Typically this is carried out in controlled conditions where air, fuel and flow can all be controlled.
Incineration can also filter out harmful particles (such as dioxins) from the fumes, and then reuses the heat to create hot water/steam and/or electricity.
This is not to be confused with ‘burning’ where waste is burnt in the open air with no controls or pollution control systems in place. This is highly harmful to the environment and people’s health.
Further reading on incineration: