If I don't possess a PAN card, am I still required to pay taxes?

Yes you always and anyways counted for tax payment for being a indian Citizen despite holding/not holding PAN, nevertheless your income should be more than slabs. 

P.S. aadhar card will work the same for you.

Threshold vary on the basis of age, income sources, profession etc. please clarify 

It's the other way around, if your income is in taxable range then you must have a PAN card and must pay income tax.

Pan ke bina koi bank acc tak open mahi hoga.. yahi se sari tracking ho jayegi.

If your income us taxable( above slabs).. Then you have to file tax and of course have a PAN

if your income is not in taxable range then you should file income tax and if its in taxable range then you should file income tax

in both senarios always file your tax return if you are smart enough than only you will understand 

cash in hand zindabad so without pan u are a ratan

filing is mandatory if we go by the book

issue becomes if u never filed taxes for last 10yrs but u finished online courses for ML & AI & got a job at palo alto & need to file 1cr salary package. Thats when IT becomes interested in you & what was incomefor past years. If u plan to stay low or no income then itr is not required. 150cr population & govt cannot catch them all nor they plan to