What type of flower is this? Location : India
This does in fact look like the flower to the cactus species Selenicereus grandiflorus.
According to "Indigenous Cactus biodiversity: A viable genetic resource to fulfill multiform needs under rainfed ecosystems"1, this plant is found in India:
Different varieties of the cactus are found in India which has immense ethnomedicinal value (Table 1). Selenicereus grandiflorus (with large sweet-scented night flowering flowers) and the Opuntia stricta are found in the wasteland as hedge plants
1. Rai, M., Singh, R.K., Sharma, P.C. and Singh, L.K., 2011. Indigenous Cactus biodiversity: A viable genetic resource to fulfill multiform needs under rainfed ecosystems.