Tokyo has again been named the safest city in the world in the Safe Cities Index 2017, having earned the top spot in 2015 as well. Johannesburg came in at 50 out of 60 cities.

The report is compiled by The Economist Intelligence Unit (EIU; the research and analysis division of The Economist Group of Britain) and sponsored by NEC.

The EIU report evaluates the relative safety of 60 cities around the world based on an index composed of 49 indicators split across four categories: digital security, health security, infrastructure security, and personal security. Interviews are also conducted with 14 experts in the field, thereby making it possible to understand improvements in urban safety from various angles.

Although Tokyo earned the highest score in digital security and made improvements in health security, it did fall out of the top ten in the infrastructure security category.

America’s deteriorating infrastructure is reflected in the rankings, with San Francisco being the only US city to claim a spot in the top twenty of this category. All other cities ranked in the top 10 for the infrastructure security category are either in Europe or the Asia-Pacific region.

Tokyo’s strongest performance is in the digital security category while it has risen seven points in the health security category since 2015. However, in infrastructure security, it has fallen out of the top 10, to 12th.

In many cities, security is falling rather than rising. With two exceptions (Madrid, which is up 13 points, and Seoul, up six), cities tend to have fallen in the index since 2015. For example, New York is down 11, Lima is down 13, Johannesburg is down nine, Ho Chi Minh City is down 10 and Jakarta is down 13.

Asian and European cities remain at the top of the index. Of the cities in the top 10 positions in the overall index, four are East Asian cities (Tokyo, Singapore, Osaka and Hong Kong), while three (Amsterdam, Stockholm and Zurich) are European.

Asia and the Middle East and Africa dominate the bottom of the index. Dhaka, Yangon and Karachi are at the bottom of the list. Of the 10 cities at the bottom of the overall index, three are in South-east Asia (Manila, Ho Chi Minh City and Jakarta), two are in South Asia (Dhaka and Karachi) and two are in the Middle East and Africa (Cairo and Tehran).

Security remains closely linked to wealth but the scores of high-income cities are falling. While cities in developed economies dominate the top half of the index (with the lower half dominated by cities in poorer countries), of the 14 cities in high-income countries, the security scores of 10 have fallen since 2015.

Income is not the only factor governing city performance on security. Most of the cities in the top 10 of the index are high-income or upper middle-income cities. However, two high-income cities in the Middle East (Jeddah and Riyadh) fall below position 40 in the index.