Letters to Editor - The HinduBusinessLineSENSEX 85,213.36 -54.30NIFTY 26,027.30 -19.65CRUDEOIL 5,177.00 -51.00GOLD 134,672.00+ 1,050.00SILVER 197,500.00+ 4,649.00SENSEX 85,213.36 -54.30NIFTY 26,027.30 -19.65NIFTY 26,027.30 -19.65CRUDEOIL 5,177.00 -51.00CRUDEOIL 5,177.00 -51.00GOLD 134,672.00+ 1,050.00'; } document.getElementById("lgdv").innerHTML = htmlElements; } function numberformat(i) { return Number(parseFloat(i).toFixed(2)).toLocaleString('en', { minimumFractionDigits: 2 }) } async function gatherResponse(response) { const { headers } = response; const contentType = headers.get('content-type') || ''; if (contentType.includes('application/json')) { return await response.json() } return response.text(); } function getWidth() { if (Math.max(document.body.scrollWidth,document.documentElement.scrollWidth,document.body.offsetWidth,document.documentElement.offsetWidth,document.documentElement.clientWidth) > 991) { document.getElementById("mob").style.display = "none"; document.getElementById("lgdv").style.display = "block"; } else { document.getElementById("mob").style.display = "block"; document.getElementById("lgdv").style.display = "none"; } } getWidth();]]>Updated - December 15, 2025 at 08:47 PM.Delhi air qualityThis refers to ‘Delhi’s air quality remains ‘severe’ at 452 as thick smog blankets the capital’ (December 15). It was intriguing to observe that the National Capital Delhi continued to grapple with poor air quality on Monday, with the overall Air Quality Index (AQI) recorded at 452 at around 8 am, placing it in the ‘Severe’ category. Moreover, there seems to be no light at the end of tunnel on this count even as the Delhi government has been forced to impose Grap-IV stipulation to somehow deal therewith.Taking account of the grace air quality, the Supreme Court too has advised advocates to appear in ‘video mode’. With this issue scheduled to hearing on December 17, the judiciary is our only hope to resolve this issue.. Notably, this hot-bedded issue stands fixed for hearing on December 17.Truly speaking, Our ultimate hopes lie with the top judicial intervention alone.SK GuptaNew DelhiOxygen vs. HydrogenApropos ‘Honeywell builds RE bridge to biomass’ (December 15). In biomass conversion to biocrude via hydrothermal liquefaction, oxygen-rich compounds in raw biomass lead to high oxygen content in biocrude, causing acidity, instability, and low heating value.This necessitates deoxygenation during upgrading. Conversely, hydrogen plays a critical role in hydrodeoxygenation and hydrotreatment, enhancing the hydrogen-to-carbon ratio, reducing oxygen, and improving the higher heating value (HHV). A higher H/C ratio yields biocrude closer to fossil fuels, with better combustion properties and storage stability.Oxygen reduces biocrude quality by lowering energy density, while hydrogen improves stability and fuel potential.Thus, minimizing oxygen and maximizing hydrogen incorporation are essential for efficient biocrude production.O Prasada RaoHyderabadNPS is for retirementApropos “Fraught with risk” (December 15), expanding the NPS investment basket may dilute its core strength —simplicity and safety.Instruments like AIFs and AT1 bonds, while potentially lucrative, introduce opacity and volatility ill-suited to retirement planning. Gold and silver ETFs under equity blur asset boundaries, and IPO exposure adds timing risk.NPS has earned trust through clarity and restraint; replicating mutual fund complexity could confuse subscribers. A better path would be tiered options based on risk appetite, with clear defaults and strong disclosures. Preserving simplicity while offering choice is key to sustainable reform.K SakunthalaCoimbatorePublished on December 15, 2025Sign into Unlock benefits!Access 10 free stories per monthAccess to comment on every storySign up/Manage to our newslettersGet notified by email for early preview to new features, discounts & offers${ ind + 1 } ${ device }Last active - ${ la }