Complex sentence: It was founded in 2001 with 15 members and now has 151 member organizations in 53 countries which work towards eliminating the toilet taboo and delivering sustainable sanitation solutions worldwide.
Split into simpler sentences: It was founded in 2001 with 15 members and has now grown to 151 member organizations in 53 countries. All these members work towards eliminating the toilet taboo and delivering sustainable sanitation solutions worldwide.