When the humidity is low density because of the compressed fuel rods containing moisture with water as an element, rather than the particles themselves will not make up lesser density.
When the humidity will cause the value of low density. Since fuel briquette with more moisture, the water is the element over which the particles are held together without making a low density.
When the humidity is low density Because fuel briquette with moisture have water composition than the particles will capture the bad make density less.