With highest spike of 8,392 cases, India's COVID-19 tally reaches 1,90,535

Washington, Apr 23: Air pollution over northern India has plummeted to a 20-year-low for this time of the year, according to satellite data published by US space agency National Aeronautics and Space Administration (NASA).
The US space agency's satellite sensors observed aerosol levels at a 20-year low post the countrywide lockdown, implemented to slow the spread of the novel coronavirus.

"We knew we would see changes in atmospheric composition in many places during the lockdown," said Pawan Gupta, a Universities Space Research Association (USRA) scientist at NASA''s Marshall Space Flight Center. "But I have never seen aerosol values so low in the Indo-Gangetic Plain at this time of year," added Mr Gupta.

Acting Assistant Secretary of State for South and Central Asia Alice G Wells tweeted, "These images from NASA were taken each spring starting in 2016 and show a 20-year low in airborne particle levels over India. When India and the world are ready to work and travel again, let's not forget that collaborative action can result in cleaner air."

The data published with maps show aerosol optical depth (AOD) in 2020 compared to the average for 2016-2019. Aerosol optical depth is a measure of how light is absorbed or reflected by airborne particles as it travels through the atmosphere.

If aerosols are concentrated near the surface, an optical depth of 1 or above indicates very hazy conditions. An optical depth, or thickness, of less than 0.1 over the entire atmospheric vertical column is considered "clean." The data were retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite.

In the first few days of the lockdown, it was difficult to observe a change in the pollution signature. "We saw an aerosol decrease in the first week of the shutdown, but that was due to a combination of rain and the lockdown," said Mr Gupta.

Around March 27, heavy rain poured over vast areas of northern India and helped clear the air of aerosols. Aerosol concentrations usually increase again after such heavy precipitation.

"After the rainfall, I was really impressed that aerosol levels did not go up and return to normal. We saw a gradual decrease and things have been staying at the level we might expect without anthropogenic emissions," Mr Gupta said.

On March 25, the Indian government placed its 1.3 billion citizens under a strict lockdown to reduce the spread of COVID-19. The countrywide mandate decreased activity at factories and severely reduced car, bus, truck and airplane traffic. Every year, aerosols from anthropogenic (human-made) sources contribute to unhealthy levels of air pollution in many Indian cities.

Aerosols are tiny solid and liquid particles suspended in the air that reduce visibility and can damage the human lungs and heart.

In southern India though, the story is a little hazier. Satellite data show aerosol levels have not yet decreased to the same extent. In fact, levels seem to be slightly higher than in the past four years. The reasons are unclear but could be related to recent weather patterns, agricultural fires, winds or other factors.

"This a model scientific experiment," Robert Levy, program leader for NASA's MODIS aerosol products, said about the lockdown and its effects on pollution.

"We have a unique opportunity to learn how the atmosphere reacts to sharp and sudden reductions in emissions from certain sectors. This can help us separate how natural and human sources of aerosols affect the atmosphere," Mr Levy added.

New Delhi, Jan 7: When a reign of terror was unleashed by "masked goons" in the Jawaharlal Nehru University (JNU) on Sunday, Delhi Police registered two cases against varsity students union president Aishe Ghosh, who was badly injured in the attack, within a span of five minutes.

The registration of cases on two separate complaints against Ghosh and other students filed by JNU security department on January 3 and January 4 were registered on Sunday night when the violence was on, triggering questions about the motive behind the timing.

While the FIRs against Ghosh and others were registered between 8.44 pm and 8.49 pm after the JNUSU president was admitted to AIIMS, an FIR on the Sunday violence was registered on Monday at 5.36 am against unknown persons. The Sunday violence case has been transferred to Crime Branch for further investigations.

Questions are being raised over the registration of FIRs on Sunday while the complaints were filed on the previous days. Students allege that it was an afterthought from the police and authorities, as a nationwide outrage erupted as soon as the violence was reported.

Delhi Police is under attack for not coming to the aid of students targeted by the mob of ABVP activists armed with iron rods and sticks who went on a rampage on the campus. While no single person in the Sunday violence was arrested, the police are also accused of being a "mute spectator" by allowing the rioters to leave the campus without being arrested.

In its complaints, the JNU Security Department has alleged that Ghosh and others entered into a verbal and physical scuffle with security guards, including women, when officials tried to open the Centre for Information System (CIS) that was blocked by students protesting against the fee hike and registration process.

While the January 3 complaint claims that the students switched off the power supply to the CIS and evicted staff forcefully, the January 4 complaint alleged that they damaged the information system.

They also claimed the students damaged the servers, made it dysfunctional, severely damaged optic fibre cables and broke the biometric system in the CIS. The complaint also cited a Supreme Court order that prevented any protest within 100 metres of Administration Block and claimed the students violated the direction.

The FIR filed on Sunday violence on the basis of the statement of Inspector Anand Yadav said that the first phase of violence was reported at 3.45 pm when "40-50 unidentified" people who had "covered their faces" attacked students in Periyar Hostel and the situation was brought under control.

However at around 7 pm, "50-60 people with rods in their hands" targeted students in Sabarmati Hostel in which students were attacked and public property destroyed.

The FIR said that students were injured but skipped the mention of the attack on teachers, who were injured. At least two faculty members Sucharita Sen and Ameet Parameswaran were taken to AIIMS while several other teachers suffered minor injuries.