Bharti Airtel CEO Gopal Vittal on Wednesday asserted that Average Revenue Per User (ARPUs) rising to Rs 300-level is "critical" for respectable return of capital employed, and hoped that it will "happen in due course". The top honcho also outlined the 'future of Airtel' strategy entailing broad themes around a resilient and diverse portfolio, rural push into high-potential villages, and opportunities in the top 150 cities, among others.