Moderate or intense low oxygen dilution (MILD) combustion plays a significant role in the mitigation of combustion-generated pollutants and greenhouse gases whilst meeting thermal efficiency needs. However, due to the lack of the fundamental knowledge on this combustion, there is a misconception that MILD combustion should be established by high preheating of the air, which has limited its application. Our research and development on this combustion has been performed for several years. We have found that the requirements for establishing the MILD combustion are more relaxed than previously. It is also revealed that this combustion of different type, i.e., non-premixed, partially premixed and fully premixed, can be achieved by firing variou...