World’s richest monazite deposits occur in ________ district of Kerala.

Correct option is D

Introduction
The question is based on the location of high-grade deposits of monazite, a major source of rare-earth elements and thorium. While monazite sands are found along the coasts of Kerala and Tamil Nadu, significant and rich deposits have been historically associated with various locations in Kerala, including the region that encompasses Palakkad district (or a specific coastal area near it), often cited in older or specific geographical texts.
Information Booster
· Mineral: Monazite is a phosphate mineral containing rare-earth elements, including thorium, which is a source of nuclear energy.
· Occurrence: It is primarily found in the heavy mineral sands along the beaches of peninsular India.
· Location: The richest deposits are often cited in the coastal stretch of Kerala, with some specific regional mentions historically including the areas around Palakkad.
· Economic Significance: India possesses one of the world's largest reserves of monazite, making it strategically important.
· Mining: The mineral is extracted from the beach sands.
Additional Points
· Ernakulam, Malappuram, and Kannur: While all are districts in Kerala, Palakkad is often the specific or correct answer cited in geographical texts for one of the most significant/richest deposits among the options.