The correct answer is Hand pump/Tube well.

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• The census 2001 collected data on amenities and assets available to each household in the country.
• Highlight from the data collected are as follows:
  • 74 million (38.5%) households, out of 192 million households in the country have only one dwelling room for living.
  • Drinking water facility is available within the premise to 75 million (39.0%) households only.
  • 32 million (16.7%) households have to fetch drinking water from sources that are at least 500 meters away in the case of towns.
  • Hand pump/Tube well is the most popular source of drinking water reported to be used by 79 million (41.2%) households.
  • Electricity as the source of lighting is available to 107 million (55.8%) households.
  • Only 69 million households (36.1%) have bathrooms within the house.
  • 123 million (64.0%) households do not have a latrine within the house.
  • Firewood is still the most used source of fuel for cooking reported by 101 million (52.5%) households in the country.
  • LPG as fuel for cooking is used by 34 million (17.5%) households.
  • Availability of assets portrays a varied picture. Whereas 67 million (35.1%) households have Radio or Transistor, Television is available to 61 million (31.6%) households in the country.

• Census is nothing but a process of collecting, compiling, analyzing, evaluating, publishing, and disseminating statistical data regarding the population.
  • It covers demographic, social, and economic data and is provided as of a particular date. 
• Census operations started in India long back during the period of the Maurya dynasty.
  • It was systematized during the years 1865 to 1872.
  • it has been conducted uninterruptedly from the year 1881 being a trustworthy resource of information.
• As per the 2011 Census, Nagaland states has recorded a decrease in population.
  • Nagaland is the only Indian state which has a negative growth rate of -0.58% in census 2011.
  • The growth rate of the Indian population was 17.69% between 2001 to 2011.
  • Dadra and Nagar Haveli is growing at a rate of 55.88% annually.
    • The second-fastest growth is recorded in Daman & Diu at 53.76% in census 2011.
  • India has 641,000 inhabited villages and 72.2 per cent of the total population reside in these rural areas.