1. Less than a third of India's 1.2 billion people have access to sanitation and more than 186,000 children under five die every year from diarrhoeal diseases caused by unsafe water and poor sanitation, according to the charity WaterAid.
A United Nations report in May said half of India's population still practise open defecation - putting them at risk of cholera, diarrhoea, dysentery, hepatitis A and typhoid. The resulting diseases and deaths cause major economic losses, and a World Bank report in 2006 estimated that India was losing 6.4 percent of GDP annually because of poor access to sanitation.
2. According to WaterAid research, about 16 million Indians a year gain access to a basic toilet. This will need to increase to more than 100 million a year if the whole population is to have a toilet by 2019.
3. Swachh Bharat Abhiyan, or Clean India Mission, is being launched on the birthday of independence leader Mahatma Gandhi - a public holiday - and aims to inform people about the link between sanitation and public health.
4. Indian towns and cities are littered with garbage, the result of massive urban migration, poor civic planning and inadequate waste disposal systems, and rivers and lakes are polluted with sewage and industrial effluents.
5. While Prime Minister is expected to take to the narrow lanes of a north Delhi slum on Thursday for a photo opportunity, ministers and other government officials have been ordered to clean their offices - including their toilets.
6. Narendra Modi government has made building toilets a priority and he has pledged that every household will have a toilet by 2019.
7. Many civil society organisations and companies have also joined the campaign, spreading awareness in urban slums and villages by putting on street plays about rubbish disposal, handing out leaflets about washing hands and even giving out broomsticks to members of the public.
8. Industry chamber CII has announced it would mobilise its members to build 10,000 toilets across the country by 2015-16.
Earlier a number of companies including Tata Consultancy Services and Bharti Foundation, an arm of Bharti Enterprises had pledged a total of Rs 300 crore each to build toilets in schools. Vedanta, which has oil and gas wells, mines and power stations, said it was already constructing 30,000 toilets in rural Rajasthan and had plans to build 10,000 more.
9. The government has also set up a Swachchh Bharat Kosh, encouraging companies to donate funds from their CSR budget to improve sanitation facilities in the country.
10. Aid workers said that while increased investment in infrastructure was important, there must also be a change in attitudes.