Water boils at a lower temperature at high altitudes, because

Water boils at a lower temperature at high altitudes, because

the air pressure is less
outside temperature is less
latent heat is less
None of the above
This question was previously asked in
UPSC NDA-2 – 2017
Water boils at a lower temperature at high altitudes because the atmospheric pressure is lower. Boiling occurs when the vapor pressure of the liquid equals the surrounding atmospheric pressure. With lower external pressure, a lower temperature is needed for water’s vapor pressure to reach that level.
Boiling point is the temperature at which the vapor pressure of a liquid equals the ambient atmospheric pressure. Pressure decreases with increasing altitude, leading to a lower boiling point.
At sea level, the boiling point of water is 100°C (212°F) at standard atmospheric pressure. At significantly higher altitudes, such as in mountainous regions, the boiling point can be several degrees lower. For example, at an altitude of 5,000 feet (approx 1500m), water boils at about 95°C (203°F). This is why cooking times often need to be adjusted at high altitudes.