To determine which city is nearest to the equator, we need to consider their latitude coordinates. The closer a city`s latitude is to 0 degrees, the closer it is to the equator.

Option 1: Colombo, Sri Lanka

Colombo is located at approximately 6.9271° N latitude. While this is relatively close to the equator, there are other cities in the options that are even closer.

Option 2: Jakarta, Indonesia

Jakarta, the capital city of Indonesia, is situated at approximately 6.2088° S latitude. This means that Jakarta is below the equator and not the nearest city to it.

Option 3: Manila, Philippines

Manila, the capital city of the Philippines, is located at around 14.5995° N latitude. While Manila is also relatively close to the equator, there is still a city that is closer.

Option 4: Singapore

Singapore is a city-state located at approximately 1.3521° N latitude. This makes it the nearest city to the equator among the options provided. Being just a little over 1 degree north of the equator, Singapore is the correct answer to the question.

It`s worth noting that proximity to the equator has various implications. Cities closer to the equator generally experience warmer climates due to the more direct sunlight received. They may also have different flora and fauna compared to cities farther away from the equator. The equator itself is an imaginary line that divides the Earth into the Northern Hemisphere and the Southern Hemisphere. It is an important reference point for various scientific and geographical measurements.