Columbus and his crew reached the Caribbean, they were the first Europeans to encounter Capsicum. They called them "peppers" because, like black pepper of the genus Piper known in Europe, they have a spicy, hot taste unlike other foods. Distribution to Asia Chili peppers spread to Asia through their introduction by Portuguese traders, who—aware of their trade value and resemblance to the spiciness of black pepper—promoted their commerce in the Asian spice trade routes. They were introduced in India by the Portuguese towards the end of the 16th century. In 21st-century Asian cuisine, chili peppers are commonly used across many regions. Production In 2020, 36 million tonnes of green chili peppers were produced worldwide, with China producing 46% of the total. Species and cultivars There are five domesticated species of chili peppers: Capsicum annuum includes many common varieties such as bell peppers, wax, cayenne, jalapeños, Thai peppers, chiltepin, and all forms of New Mexico chile. Capsicum frutescens includes malagueta, tabasco, piri piri, and Malawian Kambuzi. Capsicum chinense includes the hottest peppers such as the naga, habanero, Datil and Scotch bonnet. Capsicum pubescens includes the South American rocoto peppers. Capsicum baccatum includes the South American aji peppers. Though there are only a few commonly used species, there are many cultivars and methods of preparing chili peppers that have different names for culinary use. Green and red bell peppers, for example, are the same cultivar of C. annuum. Unripe peppers are green (although peppers that do not turn red on ripening have been bred). In the same species are the jalapeño, the poblano (which, when dried, is referred to as ancho), New Mexico, serrano, and other cultivars. Peppers are commonly broken down into two groupings: bell peppers (UK: sweet peppers) and hot peppers. Most popular pepper varieties are seen as falling into one of these categories or a cross between them. Intensity The substances that give chili peppers their pungency (spicy heat) when ingested or applied topically are capsaicin (8-methyl-N-vanillyl-6-nonenamide) and several related chemicals, collectively called capsaicinoids. The quantity of capsaicin varies by variety, and on growing conditions. Water-stressed peppers usually produce stronger pods. When a habanero plant is stressed, by absorbing low water for example, the concentration of capsaicin increases in some parts of the fruit. When peppers are consumed by mammals such as humans, capsaicin binds with pain receptors in the mouth and throat, potentially evoking pain via spinal relays