india

Updated: Oct 24, 2019 02:11 IST

Rising income and improved access to sanitation facilities has led to a decrease in disease-causing bacteria that cause acute diarrhoea in groundwater, according to a study by researchers from Indian Institute of Technology, Kharagpur.

Open defecation is a major contaminant of groundwater, which is the most common source of drinking water in India. Acute diarrhoea is the cause of 9% of all deaths among children under the age of five.

On October 2, Prime Minister Narendra Modi declared India to be open defecation free with toilet coverage increasing from 38.7% in 2014 to 100% in 2019.

The study, published in a Nature group of journals, Scientific Reports on Wednesday, shows that the concentration of faecal coliform in groundwater reduced by 38.5% between 2002 and 2017. Coliform are organisms that are found in the environment and the faeces of warm-blooded animals; their presence is used as a proxy for pathogens in water samples.

“This is probably the first time we are systematically studying the actual impact of improvement in sanitation conditions in India and its impact on the drinking water quality and health. For the study, we have mainly used government data sources for drinking water and health parameters and used NASA images of nightlight in the areas as a measure of urbanisation and economic development,” said Abhijit Mukherjee, the lead author of the paper and the associate professor of hydrogeology in the department of geology and geophysics at IIT Kharagpur.

The progress, however, is not uniform across regions. Of the 7,010 blocks that were covered in the study, nearly 43% or 3,000 blocks showed over 90% reduction in faecal coliform during the study period. It decreased by 70-90% in nearly 23% of the regions, and 50- 70% in 7.1% of the study regions.

In 24% of the blocks studied, the faecal coliform concentration in groundwater went down by less than 50%.

“We largely saw that these reductions in faecal coliform in drinking water and the cases of acute diarrhoea correlated highly with economic development and urbanisation,” said Mukherjee.

The study clearly shows a relation between the Prime Minister’s Swacch Bharat Mission and improvement in water quality and health.

Analysis of the data shows that the rate of decrease in faecal coliform concentrations was 3.09% and that of acute diarrhoea 2.69% per year for the last three decades. Since 2014, when the mission was launched, the average pace of this change increased drastically to 6.02% and 7.96% per year respectively.

“Improving sanitation and access to safe drinking water will not only reduce bacterial diarrhoea and the resulting deaths in children, but also improve various nutritional parameters,” said Dr KC Tamaria, paediatric consultant at Safdarjung hospital.

The researchers, however, saw that in the group of blocks that showed minimal improvement during the study period, the improvement in the economic condition and access to sanitation did not have strong correlation with better health outcomes.

“So, we looked at other parameters of human development such as improper use of the sanitation facilities and literacy rate. As we know, many people believe having a toilet in their homes is impure and prefer open defecation. In the fourth category, we found that these human development parameters have a stronger influence on health rather than just the presence of the sanitation facilities or economic development,” said Mukherjee.

Thus, policymakers have to prepare customised strategies for providing access to clean drinking water to all of the residents, the study concludes.