Nepal Population Estimates As of May 1, 2015 for More on Methodology, Updates and Datasets: &
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Nepal Population Estimates as of May 1, 2015 For more on methodology, updates and datasets: www.flowminder.org & www.worldpop.org The Flowminder team pioneered the analysis of mobile network data to support responses to natural disasters and epidemics (Zanzibar 2009 malaria, Haiti 2010 earthquake and cholera outbreak). WorldPop is the leading open data repository for population densities and distributions, and is Flowminder’s main dissemination platform. Nepal has 23 million mobile phone subscribers out of a population of 27 million people. Ncell has a market share of 46% [1]. For these estimates we analyze the movements of de-identified Ncell SIM cards which made or received at least one call during the week prior to the earthquake (April 25) and which also made or received at least one call after the earthquake. The former criterion excludes relief workers arriving after the earthquake, while the latter excludes SIM cards that were lost or destroyed in the earthquake. Population movement estimates are calculated by combining de-identified data on SIM card movements with available population data. Changes in mobility pattern are identified by comparing SIM card movements to normal pre-earthquake movements. Estimates will be updated and calibrated as more data becomes available. Processing infrastructure is currently being developed to allow timely future updates. Mobile phone use is relatively lower in several groups including women, children, the elderly, and the poorest. If these groups have substantially different movement patterns than groups with high mobile phone use, results will be biased. In general the relative distributions of flows across the country are more reliable than absolute numbers given per area. Both types of estimates will improve over time with additional data. Our previous field projects in Haiti and Kenya show that overall estimates of mobility corresponded well to population-level data [2-3], but the estimates provided here should be interpreted with the above mentioned caveats in mind. [1] Nepal Telecommunications Authority, NTA-MIS-94, January 2015 [2] Bengtsson et al. (2011) Improved response to disasters and outbreaks with mobile phone data: a post-earthquake geospatial study of Haiti [3] Wesolowski et al. (2013) The impact of biases in mobile phone ownership on estimates of human mobility Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 1 Produced 8 May 2015 Nepal Population Estimates as of May 1, 2015 Contents 1. Inflows to all districts 2. Kathmandu Valley (Kathmandu, Bhaktapur and Lalitpur districts) 3. Dhading District 4. Dolakha District 5. Gorkha District (epicenter) 6. Kabhrepalanchok District 7. Makawanpur District 8. Nuwakot District 9. Okhaldhunga District 10. Ramechhap District 11. Rasuwa District 12. Sindhupalchok District Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 2 Produced 8 May 2015 Nepal Population Estimates Above normal inflow to each district as of May 1, 2015 (negative numbers indicate less incoming people than normal) 1. Overview Population flows between districts are large under normal conditions. Here we present, for each district, the estimated above-normal inflows from all other districts. Inflows to a district are composed of people leaving their home area to come into the district, people returning to their home district after temporary visits elsewhere, and Nepalese relief workers (relief workers coming in after the earthquake are excluded). These estimates currently do not distinguish between these three groups. [1] www.worldpop.org Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 3 Produced 8 May 2015 Pre-earthquake population Population outflow Population inflow (above normal) (above normal) Nepal Population Estimates as of May 1, 2015 2.8m +390,000 -247,000 (246,000~540,000) (-155,000~-339,000) 2. Kathmandu Valley Above normal flows from Kathmandu Valley to other districts Kathmandu Valley is here defined as the districts Kathmandu, Bhaktapur and Lalitpur. Kathmandu Valley is one of the most densely populated areas in Nepal and home to ca 2.8 m people [1]. Key findings: ➔ An estimated 390,000 people more than normal had left the Kathmandu valley - comparing May 1 with the day before the earthquake April 24 (ratio to the population: 14%). ➔ An estimated 247,000 persons less than normal had come into the area during the same period(ratio to the population: 8.8%) ➔ People leaving Kathmandu Valley went to a large number of areas, notably the populous areas in the south and the Central and West Development Regions. Above normal flows from Kathmandu Valley to other [1] www.worldpop.org districts (comparing pre-earthquake April 24 and May 1). Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 4 Produced 8 May 2015 Pre-earthquake population Population outflow Population inflow (above normal) (above normal) Nepal Population Estimates as of May 1, 2015 361,000 -2,800 +26,000 (-1,800~-3,900) (16,000~35,000) 3. Dhading district Above normal flows from Dhading to other districts Dhading district is home to 361,000 people under normal conditions [1]. Key findings: ➔ An estimated 2,800 people less than normal had left Dhading - comparing May 1 with the day before the earthquake, April 24 (ratio to the population 0.8%). ➔ An estimated 26,000 persons more than normal had come into Dhading during the same period (ratio to the population 7.2%). ➔ Under normal conditions, people leaving Dhading often travel to Kathmandu Valley. This flow was dramatically reduced, and flows to Gorkha and Nuwakot significantly increased. Above normal flows from Dhading to other districts [1] www.worldpop.org (comparing pre-earthquake April 24 and May 1). Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 5 Produced 8 May 2015 Pre-earthquake population Population outflow Population inflow (above normal) (above normal) Nepal Population Estimates as of May 1, 2015 198,000 +3,500 -15,000 (2,200~4,800) (-9,000~-20,000) 4. Dolakha district Above normal flows from Dolakha to other districts Dolakha district is home to 198,000 people under normal conditions [1]. Key findings: ➔ An estimated 3,500 people more than normal had left Dolakha - comparing May 1 with the day before the earthquake April 24 (ratio to the population 1.8%). ➔ An estimated 15,000 persons less than normal had come into Dolakha during the same period (ratio to the population 7.6%). ➔ More people than usual moved from Dolakha to neighbouring districts, including Sindhuli, Ramechhap and Kabhrepalanchok. Above normal flows from Dolakha to other districts [1] www.worldpop.org (comparing pre-earthquake April 24 and May 1). Contacts: Flowminder.org is a non-profit organization registered in Stockholm, Sweden. Ncell is a mobile operator in Nepal [email protected] +41 78 964 88 28 and part of the TeliaSonera group. Analyses are based on de-identified mobile network data and conducted in [email protected] +46 70 893 88 37 accordance with mobile industry (GSMA) Guidelines on the protection of privacy in the use of mobile phone data for [email protected] +44 7703 392 192 responding to the Ebola outbreak, published October 2014. 6 Produced 8 May 2015 Pre-earthquake population Population outflow Population inflow (above normal) (above normal) Nepal Population Estimates as of May 1, 2015 290,000 -3,600 +41,000 (-2,300~-5,000) (25,000~56,000) 5. Gorkha district (epicenter) Above normal flows from Gorkha to other districts Gorkha district is home to 290,000 people under normal conditions [1].