Why does diesel burn with a smokier flame than petrol?

Diesel burns with a smokier flame than petrol primarily because it has a higher carbon content and contains larger hydrocarbon molecules. During combustion, the incomplete combustion of these larger molecules results in the production of soot and particulate matter, which contributes to the smokiness. Additionally, diesel engines operate at higher compression ratiOS, which can lead to a less efficient burn compared to petrol engines, further increasing smoke production.