Does a fasting person break their fast simply when the sun disappears from their sight in a city with buildings, or do they wait for darkness to set in?

The Shari'ah has clearly defined the sign of the end of fasting, which is the sunset below the horizon, as stated in the Almighty's saying: (Then complete the fast until the night), and the Prophet's (peace be upon him) saying: (When the night approaches from here, and the day departs from here, and the sun sets: then the fasting person has broken his fast). This is the consensus of Muslims. The meaning of sunset is the complete disappearance of the sun's disc, and the remaining redness in the sky is not to be considered.

If the fasting person is in a place where he can see the sunset, such as a desert or an open space, he breaks his fast when the entire disc of the sun disappears. However, if he is in a place where it is difficult to see the sunset, such as cities where buildings obstruct the view of the horizon, it is not permissible for him to break his fast merely because the sun disappears from his sight. Rather, he infers its setting by the disappearance of its rays from tall walls, or by the approach of night from the east, which is the appearance of darkness in the sky from the east. This is indicated by the aforementioned Hadith (definition) of the Prophet (peace be upon him), as the approach of night, the departure of day, and the setting of the sun are all interrelated, and one of them may be more apparent to use as an indicator for the others.