New Delhi: On 14 September, two key oil plants in Abqaik and Khurais in Saudi Arabia were hit by a drone attack, disrupting half of the country's crude oil and gas production.

Yemen rebel group Houthis, who claimed responsibility for the attack in retaliation to Saudi Arabia's continued military interference against the rebels in Yemen since 2015, said they used 10 drones, also known as UAV (unmanned aerial vehicles), without giving any details on them, to carry out the attacks.

According to a United Nations' Security Council report prepared and presented by a panel of experts in January 2019 on Yemen, Houthi rebels have been using small- and medium-sized UAVs for reconnaissance, surveillance and suicide attack.

According to the Security Council report, the most commonly used UAV in the Houthi arsenal for loitering munitions is called Qasef-1, which had a lot in common with Iranian made Ababil-2/T UAV which has been used in Yemen since 2016.

During their investigation, the security council panel found that the new UAVs are characterized by distinctive V-shaped tail fins and a more powerful engine. The Samad 2/3 UAV carries a warhead with 18 kg of explosives mixed with ball bearings.

UAVs is a broad category and includes all types of small and mid sized flying machines with no pilot in them.

They can be remote controlled by a pilot on ground or can fly autonomously following a pre-defined flight plan and can be used for anything from photography to surveillance or carrying payloads to monitoring crops and industrial sites. Advanced drones use GPS signals from satellites to connect and relay their location to the pilot.

Entry-level drones used for aerial photography use multi rotors and have limited speeds. Which is what makes them nonviable for large scale mapping or long distance inspection.

The more advanced fixed wing drones are small in size but use a fixed wing like actual aircraft instead of rotary wings. This allows it to move faster and cover longer distances. The images of the Houthi drones presented to the Security Council by the panel largely belonged to fixed wing category.

The new drone policy of India, in place from December 2018 after DGCA (Directorate General of Civil Aviation) legalised flying UAVs for personal and commercial purpose, is open to both fixed and rotary wings based drones, but requires pilots to submit the design of the drones for registration.

Under the new drone regulations, every UAV that weighs above 250g and can fly over an altitude of 50 feet has to be registered and regulated through an online platform called Digital Sky. It mandates users to register their drones, acquire a pilot licence, along with UAOP (an unmanned aircraft operator permit). Users also have to define their flight plan for every flight using the Digital Sky app. The drone can take off only after receiving permission, which gets verified by the hardware inside the drone.

If there is any infraction in the flight plan it is recorded in Digital Sky and action will be taken action against the defaulter.

All no drone-flying zones such as high security areas like airports, defence installations have been geo-fenced.

A drone policy 2.0 is being worked out to open up the use of UAVs to carry payloads by businesses. It will strengthen the regulation of drones with the new NPNT (no permission no take off) rule, which will not allow a drone to fly without real time permission for every flight.

While drones that can only capture photos is annoying, the fact that soon we will have drones that can carry objects is a bit scary as they can be used to carry out air strikes on people and property.

"It is quite possible for a terrorist group to get a drone and use it to carry out attacks without going to the digital NPNT system. Once the NPNT system gets in place, authorities will be able to spot any unregistered drone in the sky. However, it will only regulate to a certain level because anybody can still get the drones in the sky," warned Karan Kamdar, CEO of 1 Martian Way Corporation, a Mumbai based startup that makes embedded AI products for drones and robots.

The fact that anyone can build and use a rogue drone without Geo-fencing the hardware or software is concerning. Outside of Digital Sky, avoiding detection is not that difficult, as there are smaller drones built with sophisticated material which can easily carry larger pieces of payloads weighing 10 kg and even more.

Kamdar feels that the government should first try to have some kind of an anti drone system in place physically in the sky which can shoot or bring down rogue drones quickly.

While in sensitive areas like border, airport and defence installation, any flying objects sending out radio signals can be detected through radar (radio detection and ranging), such mechanisms are not available in public airspace.

Gokul Kamaravelu of Skylark Drones, agrees that Digital Sky has its limitations, but it doesn't completely lack teeth.

According to Ohio University, lack of comprehensive regulations necessary to safely facilitate integration of UAVs into the national airspace system is a major issue surrounding UAVs.

Kamaravelu adds, "right now, the regulation is structured to have a live management management system where authorities know, at all times, what kind of UAVs are flying and in what part of the airspace. To regulate them, it also required manufacturers to even register the parts they have imported. So if there is a misuse, the paper trail can at least reveal how a drone got into the system."