Explanation:

In the absence of any authentic data base regarding the location of insanitary latrines, it has been decided to seek the help of NGOs, Social Organisations and general public for collection and compilation of the data.

• For this purpose, Union Minister for Social Justice and Empowerment Shri Thaawarchand Gehlot launched a Mobile Application “Swachhata Abhiyan” in New Delhi recently.

Swachhata Abhiyan App

• The app has been developed to identify and geotag the data of insanitary latrines and manual scavengers so that the insanitary latrines can be replaced with sanitary latrines and rehabilitate all the manual scavengers to provide dignity of life to them. 
• He urged all citizens of the country to download the above application and if they notice any insanitary latrine or manual scavenger, their details may be uploaded using the application.

Background

• Traditionally persons of a section of the society has been engaged or employed to clean undecomposed excreta from the dry latrines and latrines from which excreta is flushed into open drains.
• Such workers are called manual scavengers.
• Existence of the above mentioned type of insanitary latrines has been the main reason for manual scavenging.
• The Census 2011 reported the existence of more than 26 Lakh insanitary latrines in the country.
• Existence of insanitary latrines is the main reason for manual scavenging.

Construction/ maintenance of insanitary latrines and engagement of persons for manual scavenging is prohibited under “Prohibition of Employment as Manual Scavengers and their Rehabilitation Act, 2013”.

• This Act also mandates the local authorities to ensure survey of insanitary latrines, their demolition and construction of sanitary latrines in their place.
• Most of the insanitary latrines have been converted into sanitary latrines under the Swachh Bharat Mission implemented by the Ministry of Housing and Urban Affairs and the Department of drinking water and Sanitation in urban and rural areas respectively.
• The country has been declared open defecation free.

Hence option 4th is correct.