According to Vastu Shastra and some schools of astrology, purchasing a house with a hill, mountain, or tall building directly to the north is generally discouraged. The north is considered an auspicious direction associated with Kubera, the god of wealth, and is believed to be a gateway for positive energies. An obstruction in the north, such as a large natural or man-made structure, is thought to impede the flow of these beneficial energies, potentially affecting the residents' prosperity, career prospects, and overall well-being. It is believed that such a placement can create blockages and hinder opportunities for growth. While these are traditional guidelines, it's always recommended to consult with a Vastu expert or astrologer for a personalized assessment of a property's suitability, as other factors like the plot's shape, slope, and internal layout also play a significant role.