Rịba ama amaokwu a dị n'okpuru ma zaa ajụjụ ahụ mgbe e mesịrị n'otu asụsụ ahụ dị ka amaokwu ahụ:  Ebe e si agafe: Ala Indo-Gangetic, nke a makwaara dị ka Indus-Ganga Plain na North Indian River Plain, bụ ala na-eme nri nke dị nde 630-acre (2.5 nde km2) nke na-ekpuchi mpaghara ugwu nke mpaghara India, gụnyere ọtụtụ n'ebe ugwu na ọwụwa anyanwụ India, akụkụ ọwụwa anyanwụ nke Pakistan, ihe fọrọ nke nta ka ọ bụrụ Bangladesh niile na ala dị larịị nke ndịda Nepal. A na-akpọ ógbè ahụ aha osimiri Indus na Ganges, ọ na-agụnyekwa ọtụtụ ógbè mepere emepe. Ugwu Himalaya, nke na-enye ọtụtụ osimiri ya nri ma bụrụkwa isi iyi nke alluvium na-eme nri nke e debere n'ógbè ahụ site n'osimiri abụọ ahụ. Akụkụ ndịda nke mbara ọzara ahụ bụ Chota Nagpur Plateau. N'ebe ọdịda anyanwụ, a na-ahụ Ugwu Iran.  Ajụjụ: Olee otú ọtụtụ acres dị na North Indian River Plain?
630-million-acre