Paucity (Scarcity): The extreme drought caused a paucity (scarcity) of fresh fruit, which raised market prices.
Mitigate (Lessen/Reduce): The government planted trees to mitigate (lessen/reduce) the heat effect from the concrete buildings.
Ubiquitous (Everywhere): Smartphones are now ubiquitous (everywhere) because it is rare to see anyone in public without one.