Why was WMAP placed near the second Lagrangian point?

The Wilkinson Microwave Anisotropy Probe (WMAP) was positioned near the second Lagrangian point (L2) primarily to isolate the spacecraft from radio emissions originating from Earth and the Moon.1

By operating at this location—situated 1.5 million kilometers opposite the Sun from Earth—the probe could conduct its sensitive measurements of the cosmic microwave background without the interference of terrestrial or lunar radio noise, while avoiding the need for a more distant trajectory that would have complicated tracking. Additionally, this location is highly advantageous for space observatories because it allows for the use of a sun shield to effectively block heat and light from the Sun, Earth, and the Moon.12