Delhi, a tropical indian megacity, experiences one of the most severe air pollution in the world, linked with diverse anthropogenic and biomass burning emissions. First phase of COVID-19 lockdown in India, implemented during 25 March to 14 April 2020 resulted in a dramatic near-zeroing of various activities (e.g. traffic, industries, constructions), except the "essential services". Here, we analysed variations in the fine particulate matter (PM 2.5) over the Delhi-National Capital Region. Measurements revealed large reductions (by 40-70%) in PM 2.5 during the first week of lockdown (25-31 March 2020) as compared to the pre-lockdown conditions. However, O 3 pollution remained high during the lockdown due to non-linear chemistry and dynamics under low aerosol loading. Notably, events of enhanced pM 2.5 levels (300-400 µg m −3) were observed during night and early morning hours in the first week of April after air temperatures fell close to the dew-point (~ 15-17 °C). A haze formation mechanism is suggested through uplifting of fine particles, which is reinforced by condensation of moisture following the sunrise. The study highlights a highly complex interplay between the baseline pollution and meteorology leading to counter intuitive enhancements in pollution, besides an overall improvement in air quality during the COVID-19 lockdown in this part of the world. The pandemic due to spread of novel Corona virus, commonly known as the COVID-19, has led to partial or complete lockdown in several countries around the world. The spread of deadly virus has caused deaths estimated to more than two hundred thousand people over a period of December 2019-April 2020. However, air pollutants and COVID-19 are linked to have played a major role in huge number of deaths 1,2. In order to contain its impact in India, the first phase of complete lockdown imposed from 25 March to 14 April 2020, which was further extended till 03 May 2020. As a result, the transport, construction works, industries and other commercial activities, which could have injected pollutants or produce dust, are stopped and remained at its minimal level. Unprecedented reductions in anthropogenic activities yielded to very low values of emissions resulting in significantly improved air quality over the Delhi-National Capital Region (NCR) [up to 50% reduction in fine particle

Tele-operation of a Lunar rover from a control station on Earth involves a latency of several seconds due primarily to the finite speed (light-speed) of command and sensor signals, and this latency creates a difficult control task for the human operator. Two predictive displays, which seek to aid viewer perception of present events, were designed and evaluated for the specific task of driving a rover with multi-second latency. These displays provided visual information to the human operator on the rover's real-time locomotion, as predicted from control inputs executed by the operator. A human-subject experiment with 12 participants was conducted in which the participants navigated an actual rover through obstacle courses. There were four experimental conditions repeated by each participant: (1) delayed video feed only, (2, 3) two predictive displays based on delayed video feed, and (4) a reference condition of video feed with no delay. Inferential statistics show that both predictive displays significantly improved performance in terms of time taken to complete the courses, and one of the displays facilitated performance approaching that with no delay. No trends were observed in terms of collisions with or encroachments near obstacles.

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