Mobile crowdsensing (MCS) is a technique where people with computing and sensing devices such as smartphones collectively share data that are of potential interest to the rest of society. MCS includes two different trends (i) mobile sensing, which shares raw data generated from the sensors that are embedded in mobile devices, and (ii) social sensing, which uses the information shared by people in online social networks (OSNs). In this study, the authors present the timeline evolution of the COVID-19 pandemic in Spain, and summarise the MCS research efforts that are being undertaken by the Spanish community to address COVID-19 outbreak. Indeed, the COVID-19 pandemic is putting today's society at risk; lockdown and social distancing measures proposed by governments are dramatically affecting economies. In this regard, MCS tools can become a powerful solution to provide smart quarantine strategies in periods of a steep decrease of infections, or new outbreaks.

While the world still struggles against the devastating effects of the COVID-19 pandemic, governments and organisations are discussing how new technologies can be exploited to relieve its impacts and how future pandemics can be avoided or minimised. Among the envisioned solutions, the development of more efficient and widespread smart city initiatives can improve the way critical data is retrieved, processed, stored, and disseminated, potentially improving the detection and mitigation of outbreaks while reducing the execution time when taking critical actions. In fact, some first responses to this pandemic are exploiting different technological solutions that could be ultimately adopted in more integrated city-scale systems, opening many possibilities. Therefore, this study discusses potential solutions and review recent approaches that can be exploited in this complex scenario, describing feasible and promising development trends for the construction of the new expected health-centric smart cities.

In this work, the impact of the Coronavirus disease 2019 (COVID-19) virus in Italy is presented. This pandemic disease determined a crisis and national emergency in all parts of the world. A short vision of measures taken by the Italian Government with a view on information and communication technologies (ICT) that could allow a better management of the pandemic and a faster recovery from the national crisis is provided. The Italian lockdown has strict implications for the society from an economical, mental-health and social points of view. Novel information and communication technologies (ICT) could mitigate the impact of COVID-19 outbreak allowing novel ways to learn, to teach, to work and to live. Some insights on Internet of Things, smart tracing and tracking solutions are summarised. Moreover, some statistics on the network traffic and learning platforms used in this lockdown period are presented.

The COVID-19 is not mitigating without a vaccine, but its effect can reduce using some advance technology. Smart cities are one of the essential needs for reducing this pandemic. This study presents the role and implementation of smart city technology to minimise the COVID-19 risk. The smart city technology is used to maintain social distancing, which avoids the face-to-face interaction and physical contact. It has been observed that the position technology is used to trace the infected people. Drones and robot technology are used to work as medical staff and helpful for other essential services. It can be seen that smart healthcare is one of the advance smart city technologies, which is used to take care and treat infected people without any contact. It has also been observed that the smart delivery system is one of the contact-free technologies. It is used to deliver essential items, including groceries, food, and medicine, without any physical contact. The uses of all the above smart city technologies have been discussed widely to mitigate the COVID-19 risk.

The COVID-19 crisis has had a great impact on Japanese society. The author is rapidly going online and trying to make the transition to a new way of life. This study discusses the topics before and after the COVID-19 pandemic in Japan. Then, smart approaches to waste management for post-COVID-19 smart cities in Japan are described by illustrating the results of the author's research group. Specifically, the author states that virtual reality can be an effective solution for remote education. The work chain management system contributes to the promotion of cashless in addition to the traceability of waste. The multi-benefits mobility system that supports self-driving will contribute to the automatic garbage collection by linking it to smart garbage bins. Besides, remote control of waste incineration facilities and robotic arms in waste treatment and recycling facilities will take on more importance. The author believes that the COVID-19 crisis could be an opportunity to accelerate smart city initiatives in Japan.

Smart cities are evolving globally and many governments have invested large sums of monies to develop smart cities. This development is not a result of an overnight decision but rather, smart cities have evolved through a period of time, directly from earlier work on the digital city to ubiquitous city, green city, connected city, sustainable city, eco-city etc. The present age sees the arrival of very high-speed wireless 5G connectivity, fast GPU multi-core-based servers, big data, cloud computing, artificial intelligence, and data analytics. Many of these new technologies have supported the development and realisation of smart cities. In this study, the authors present an outline of security for smart cities and provide a deeper understanding of what we meant by securing smart cities. They discuss the applicability of existing security methods of authentication, access control, encryption, firewalls, and their appropriateness to defending a smart city. Specifically, we cover the security of data, internet, water supply, electricity supply, city brain, and other critical city services and present the possible malicious attacks on a smart city and consequences. Finally, they discuss security best practices for smart cities.