Tesla CEO Elon Musk recently took swipes at Apple, the largest company in the world, over the use of cobalt in its products. The criticism came when he was asked about the use of metal in Tesla's supply chains.

"Apple uses, I think, almost 100 percent cobalt in their batteries and cell phones and laptops, but Tesla uses no cobalt in the iron-phosphate packs, and almost none in the nickel-based chemistries," Musk said during a conference call to discuss Tesla’s earnings report on July 26.

"On on a weighted-average basis, we might use 2 percent cobalt compared to say, Apple uses 100 percent. Anyway, so it's just really not a factor."

Cobalt mining has been associated with human rights issues like forced child labour and severe environmental damage near mining locations. Apple and Tesla were accused in a human rights lawsuit over their role in the promotion of child labour.

Apple has assured it will gradually switch to recycled materials for the production of phones.

Musk also criticised Apple policy over the company’s control on the App Store and apps that are allowed on it. Apple had been facing increasing scrutiny over its App Store policies, being labelled as anti-competitive, in several lawsuits including one against Fortnite publisher Epic Games and music streaming giant Spotify.

"I think we do want to emphasise that our goal is to support the advent of sustainable energy," Musk said in response to a question about letting competitors use its charger network.

"It is not to create a walled garden and use it to bludgeon our competitors that are used by some companies."

"Apple", said Musk while faking a cough.

While the two companies do not directly compete with each other, Apple is reportedly working on its own self-driving vehicles. The project, code-named Titan, has taken several engineers and executives away from Tesla, including Doug Field who is the head of the project.