POP stands for Plaster of Paris, commonly referred as POP. The Ganesh & Durga Idols which are built during festivals Re made up of POP.
Fall Ceiling, as commonly referred, is really FALSE ceiling. many Architects/Designers also call it as Falce Ceiling.
Trend in India started with Bungalows. Their ceiling face Sun & gets heated during summer. Ceiling in India is made out of RCC . When direct sunlight hits RCC, it gets heated. After this your ceiling fan starts throwing this Hot air inside home.
False Ceiling can be done with different material. POP is most common. Next came Gypsum board. its more advance then POP. Gypsum mixture is factory made, hence there is no problem of mixing right composition. Strength of Gypsum is more then that of POP.
Many times in POP, plastic sheet/threads is used for holding the layer. Like reinforcement in RCC.
Gypsum board is factory made, hence there is consistency in thickness. POP sheet use to be 2′ x 2′ (2 feet by 2 feet) whereas Gypsum sheet can be upto 6′ x 4′ (6 feet by 4 feet). Gypsum sheet thickness of 15 mm is common. Being bigger in size, it becomes easy to work with. it is easy to screw a sheet.
Next if someone wants to spend more money, you can have PLY (plywood) in false ceiling. Instead of Gyspum, you use wood. This option would not work if your home has termite problem. It becomes important to do anti-termite treatment regularly.
In short Fall ceiling ( false ceiling ) creates insulation layer & keeps room cooler. Make sure 3 – 6 inch gap is must between RCC layer & your false ceiling.