Is an engineer who designs a agricultural plot and divides it into small pieces to be sold for construction purposes sinful, given that he does not know when this division will be implemented, and given that it is close to the building cordon? And if this act is impermissible, what should he do with the money he received for this work?

The planning of agricultural land and drawing its divisions to sell it as building land is permissible (halal), and the earnings from it are not forbidden (haram). As for whoever undertakes the actual planning and construction on this land before it enters the building zone, and the regulations prohibit that, then his adherence to the regulations is outwardly obligatory to prevent discord (fitna) and avoid punishment. Inwardly, adherence to restrictions on permissible actions is necessary if the benefit is determined or غالبة (predominant).