India is home to the world's largest number of stunted children due to a lack of toilets, dirty water and poor hygiene, according to a new study published on Tuesday.

Despite high economic growth in recent years, India has more stunted children than Nigeria, Pakistan, China and the Republic of Congo combined, with 48 million under the age of five - about 30 percent of the global total, a WaterAid report said.

Stunting is a form of malnutrition in which children are shorter than normal for their age and is largely irreversible after the age of two.