Learn Portuguese (Portugal): A habitação no centro é cada vez mais cara. - Housing in the center is increasingly expensive.

Cada vez mais translates literally to each time more. This is the standard Portuguese phrase to express increasingly or more and more. It acts like an adverb phrase, so you just place it directly before the adjective you want to intensify, which is cara in this sentence.

Why is the adjective cara feminine here?

The phrase cada vez mais does not affect how adjectives agree. The adjective cara (expensive) still has to agree in gender and number with the noun it describes. Since a habitação (housing) is feminine and singular, the adjective must be cara instead of the masculine caro.

If housing prices are changing over time, why use é (from the verb ser) instead of está (from the verb estar)?

This is a tricky distinction! Even though prices change, stating how expensive a city center is often feels like describing a general characteristic or established fact about that area, which triggers ser. However, using está (está cada vez mais cara) is also completely correct and would strongly emphasize the temporary or ongoing trend of the price increase.

Why does the sentence use no centro instead of just em centro?