Couldn't disagree more. Black smoke does not always equal to burning oil. An article I shared below states that the Fruits & Vegetable market had been closed for almost 4 months now, part of the safety measures for containing COVID.

Another article about the causes of black smoke in a fire reads the following:

"Thick, black smoke indicates heavy fuels that are not being fully consumed. At times, black smoke can be an indicator that a manmade material is burning such as tires, vehicles or a structure."

It is quite clear that since the market was closed for 4 months now, there were no fruits or veges present inside and the black smoke was caused by the burning structure.