How to send HTML email using linux command line

I need to send email with html format. I have only linux command line and command "mail".

Currently have used:

echo "To: address@example.com" > /var/www/report.csv
echo "Subject: Subject" >> /var/www/report.csv
echo "Content-Type: text/html; charset=\"us-ascii\"" >> /var/www/report.csv

echo "" >> /var/www/report.csv

mysql -u ***** -p***** -H -e "select * from users LIMIT 20" dev >> /var/www/report.csv
echo "" >> /var/www/report.csv

mail -s "Built notification" address@example.com < /var/www/report.csv

But in my mail-agent i get only plain/text.